Understanding the Deep tech, materials, energy and climate tech Landscape

The deep tech, materials, energy and climate tech technology landscape is rapidly evolving, driven by the urgent need for innovative solutions to combat climate change and transition to sustainable energy sources. A sector that is often hardware-intensive, they face unique demands such as substantial capital investments, access to advanced fabrication and testing facilities, and the necessity for specialized expertise. With increasing global emphasis on sustainability, understanding the dynamics of this industry is crucial for innovators looking to make a mark in this sector.

High Capital Requirements: Developing deep tech, materials, energy and climate tech solutions often demands substantial upfront investment, which can be a barrier for early-stage startups. This isn’t helped by the fact that climate tech investments have seen a significant shift in funding dynamics; between Q4 2022 and Q3 2023, climate tech financing dropped to $56 billion, down 29% from $79 billion in the previous year.

Shifting Investment Focus: Investors are increasingly focused on mid-stage and late-stage deals, which accounted for 37% of all climate tech deals in the first three quarters of 2024, up from around 20% in 2019. This shift indicates a more cautious investment approach, making it harder for early-stage hardware startups to secure the funding necessary for prototyping and scaling.

Underfunded Sectors: Climate tech startups in the industrials sector (industry, manufacturing and resource management) saw their share of investment capital fall from 17% in 2023 to 7% (far below what’s needed) in the first three quarters of 2024, despite being responsible for 34% of global greenhouse gas emissions. This disparity highlights the urgent need for innovative hardware solutions in sectors that are not receiving proportional funding.

Impact of Policy Initiatives: On the positive side, U.S. climate tech startups received $24.8 billion between Q4 2022 and Q3 2023, and US$24.0 billion between Q4 2023 and Q3 2024 with policy initiatives like the Inflation Reduction Act (IRA) playing a crucial role in sustaining investment levels. Startups in deep tech, materials, energy and climate tech technologies can benefit from such policies that provide financial incentives for development and commercialization.

Growing Trends: Energy-related startups took a greater share of climate tech funding to nearly 35% during the first three quarters of 2024, up from 30% in 2023, suggesting a growing interest in alternative energy such as green hydrogen and others.

Common Deep tech, materials, energy and climate tech Startup Challenges

Deep tech, materials, energy and climate tech tech is evolving, but funding–as already established–is shifting toward mid-to-late-stage startups, leaving early-stage innovators struggling. Additionally, navigating complex regulatory landscapes to accessing essential resources and expertise, these and many hurdles significantly impact their ability to transition from lab proof of concept to market-ready solutions.

Early-stage startups in this space will often stumble on these common bottlenecks:

Capital Intensity: Hardware-intensive climate tech solutions require significantly higher capital investments compared to software ventures. The ticket sizes for major climate technologies in early-stage venture capital can be five to six times higher than those in sectors like fintech or quantum computing. For instance, sectors such as sustainable fuels and hydrogen often require early-stage funding exceeding $25 million.

This high capital requirement poses a challenge for startups transitioning from proof of concept to prototype, as they must secure substantial funding before they can even begin production.

Longer Development Timelines: The time required to scale hardware-intensive solutions is notably longer than that for software companies. The average time from Series A to Series D funding for digital marketplaces is about three years, whereas climate or deep tech, materials, energy and climate tech technologies may take around seven years to achieve scale. This extended timeline can create significant hurdles for startups looking to move quickly from prototype development to market entry.

Commercial Uncertainty: Climate tech startups face greater commercial uncertainty compared to traditional tech ventures. This uncertainty stems from the dependency on various stakeholders across the value chain, which can complicate adoption decisions and delay the transition from lab prototypes to commercially viable products.

Additionally, many capital-intensive climate technologies lack proven commercial models, making it difficult for startups to demonstrate a clear path to profitability.

Funding Access: Investors may be hesitant to commit funds due to the perceived risks associated with hardware-intensive climate technologies. Traditional project investors are accustomed to lower debt levels and may shy away from long-term investments that require substantial upfront capital without immediate returns. Rising borrowing costs and economic uncertainty have slowed climate tech investment. Venture capital and private equity funding also declined, falling from $799 billion to $673 billion, reducing climate tech’s share from 9.9% to 8.3%.

Startups must therefore work to de-risk their business models by clearly articulating the engineering feasibility of their technologies and demonstrating that many components have been proven in other applications.

Regulatory Hurdles: Hardware-intensive deep tech, materials, energy and climate tech startups encounter significant regulatory hurdles that can impede their transition. Lengthy permitting processes for establishing lab and manufacturing facilities often cause delays, while compliance with stringent safety and environmental regulations requires additional resources for testing and documentation. Securing patents can be time-consuming and costly, diverting focus from product development.

Investors are typically cautious about regulatory risks, necessitating a clear understanding of compliance requirements to attract funding.

Market Competition: Established big players in this sector often dominate the deep tech, materials, energy and climate tech landscape, making it difficult for new entrants to gain traction.

The Critical Leap: From Proof of Concept to Prototype

As already established, deep tech, materials, energy and climate tech startups often encounter myriad challenges in transitioning from proof of concept to functional prototypes. This transition requires not only technical expertise but also access to specialized resources and facilities. Understanding how to bridge this gap is essential for accelerating deep tech, materials, energy and climate tech startup development. This understanding comes via exploratory phases involving:

Validation of Technology: Ensuring that the technology works as intended under real-world conditions.

Design and Engineering: Developing a prototype that meets market needs while adhering to regulatory standards.

Testing and Qualification: Rigorous testing to validate performance metrics and ensure reliability.

Despite its importance, many startups lack access to the necessary resources, expertise, and facilities to conduct prototyping phases. This is where Vetri Labs is of value by supporting these startups with the necessary infrastructure, mentorship, and guidance, enabling them to navigate this pivotal leap effectively.

Vetri Labs: Bridging the Gap

Our Lab

 Vetri Labs provides fully permitted wet lab space totalling 1,650 square feet equipped with $200k critical testing and prototyping equipment essential for climate or deep tech, materials, energy and climate tech tech development. This includes Fume hood; Ink processing; coating, Fume hood; Electrochemical workstation, Electrochemical workstation, Electrode Fabrication 80 Channel Battery Tester, Glovebox and others.

This setup eliminates traditional barriers associated with lab setup, allowing startups to focus on developing their technologies from day one without the lengthy permitting processes typically required.

Additionally, Vetri Labs fosters an environment that is:

• IP Encumbrance Free: Startups retain ownership of their intellectual property (IP), encouraging innovation without concerns about IP sharing or licensing.
• Cost Efficient: By providing immediate access to lab facilities and equipment, Vetri Labs significantly reduces capital expenditures (CAPEX) and operational expenditures (OPEX), enabling startups to allocate funds more effectively toward R&D.

Research & Development Support

 Vetri Labs offers end-to-end R&D support coming straight from industry veterans with decades of hands-on experience. Startups can leverage this expertise to navigate technical challenges effectively and accelerate their development timelines. Core services include:

• Electrochemical Characterization: Understanding material properties through advanced testing protocols.
• Techno-Economic Modeling: Assessing the feasibility and market potential of new technologies.
• Device Proof of Concept: Validating technology through practical applications.
• Materials Synthesis: Creating and optimizing novel materials with specific properties critical for deep tech, materials, energy and climate tech technologies
• Device Scale-Up: Scaling the production of prototype devices from lab-scale to commercially viable quantities

Personalized Training Programs

 Vetri Labs also emphasizes the importance of skill development through customized training programs. These courses cover essential topics such as:

– Basics of Electrochemical Science and Technology

– Fundamentals of Electrochemical Engineering

– Fundamentals of Electrochemical Test Techniques

– Fundamentals of Electrochemical Impedance Spectroscopy

– Overview of Solid-State Batteries

– Overview of Fuel cell technology

– Overview of flow battery technologies

– Overview of Electrochemical Sensors

By enhancing team expertise, startups can improve their chances of success in developing market-ready solutions.

Vetri Labs Incubator Program: A Structured Approach to Growth

 For deep tech, materials, energy and climate tech startups looking for complete hands-on mentorship, the Vetri Labs Incubator program is designed to accelerate development by providing essential resources and expertise often out of reach for early-stage ventures. The incubator is designed to guide startups through three critical phases:

Start Phase – Validate Your Big Idea:

• Collaborate with our technical experts to refine concepts and validate approaches through in-depth sessions.
• Focus on problem identification and definition, enabling startups to align their innovations with market needs.

Build Phase – Create What Matters:

• Access lab space and mentorship to develop prototypes that meet market needs.
• Support includes product development guidance and assistance in creating minimum viable products (MVPs).
• Startups benefit from immediate access to lab equipment without incurring high capital expenditures (CAPEX) or operational expenditures (OPEX).

Grow Phase – Scale Your Impact:

• Navigate market entry with guidance from our experienced mentors who have successfully scaled hard tech companies.
• Mentorship focuses on strategic partnerships and next-generation R&D efforts while helping startups achieve maturity in their current products.

The incubation program offers various engagement models tailored to support startups at different stages of their development and as per need.

Engagement Model

Vetri Labs as part of its Incubator Program does not retain ownership of intellectual property (IP) of partnering startups, fostering an environment where innovation can thrive without encumbrances.

Time to Scale

The journey from a groundbreaking idea to a market-ready deep tech, materials, energy and climate tech technology comes with a lot of bottlenecks, but it’s also ripe with opportunity. By understanding and addressing common hurdles—from funding and regulatory compliance to accessing critical resources—startups can significantly increase their chances of success. Vetri Labs is committed to bridging these gaps, providing the essential infrastructure, mentorship, and expertise needed to accelerate innovation.

If you’re a deep tech, materials tech, climate tech or clean tech startup ready to take your vision to the next level, the time to act is now. Connect with Vetri Labs and let’s build a sustainable future, one prototype at a time.

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References:

1. https://www.mckinsey.com/capabilities/strategy-and-corporate-finance/our-insights/a-different-high-growth-story-the-unique-challenges-of-climate-tech
2. https://www.pwc.com/gx/en/issues/esg/climate-tech-investment-adaptation-ai.html

Among the active cathode materials for lithium-ion batteries, Li- and Mn-rich NCMs (x Li₂MnO₃ · (1−x) LiNi_aCo_bMn_cO₂, with a + b + c = 1; often referred to as LMRNCMs) are one of the most promising materials due to their high reversible capacity. However, they need to be improved in terms of cycling performance, it has been shown that when delithiation is carried out above 80% SOC a release of oxygen lattice start. Such oxygen lattice release causes degradation of both the active cathode material and the electrolyte of the cell leading to capacity fade. Studies of these materials have revealed that the electrolyte has a great impact on this process in LMRNCMs, especially ethylene carbonate (EC).

Owing to the effect of the electrolyte in batteries containing LMRNCMs, several efforts have been taken to identify the most suitable compounds to increase their cycling performance. For this matter, fluorinated electrolytes (e.g., FEC) have shown promising results. According to the literature, it seems that FEC is more resistant to electrochemical oxidation at high overpotentials which are reflected as a superior cycling performance. Therefore, it is of great importance to elucidate the processes involved in the degradation of the battery components to develop more stable assemblies.

In a recent report, Teufl et al performed a study to evaluate the stability of EC and FEC at high potentials and the role of lattice oxygen release in the cycling performance of full cells containing LMRNCMs (Teufl et al., 2020). They proposed the implementation of on-line electrochemical mass spectrometry to identify the processes related to capacity fade. The results showed that when the full cell was operated below the onset potential of the lattice oxygen release, the performance with both electrolytes is similar. However, at higher potentials, the lattice oxygen release starts and generates chemical reactions causing the degradation of electrode and electrolyte materials. This effect is higher in the presence of ethylene carbonate, which presents a fast capacity fading related to a dramatic impedance increase. Based on these results, the authors highlighted the importance of the use of EC-free electrolytes to avoid oxygen lattice release.

The study presented by Teufl et al helped to identify the process related to the detrimental cycling performance in Li-ion batteries in the presence of EC-based electrolytes. Nevertheless, more research needs to be done to identify the most suitable materials to be used in batteries containing LMRNCMs.

Watch the discussion of this paper in our Weekly Science Review:

For further details please refer to the full paper available at https://iopscience.iop.org/article/10.1149/1945-7111/ab9e7f.

Teufl, T., Pritzl, D., Krieg, P., Strehle, B., Mendez, M. A., & Gasteiger, H. A. (2020).  Operating EC-based Electrolytes with Li- and Mn-rich NCMs: The Role of O 2 -Release on the Choice of the Cyclic Carbonate. Journal of The Electrochemical Society, 167(11), 110505. https://doi.org/10.1149/1945-7111/ab9e7f

Despite the high chemical stability of the Ti-coated electrodes, some challenges remain in terms of reaction selectivity. Secondary reactions not only can cause a decrease in the process efficiency but can lead to the deposition of byproducts on the electrode surface, affecting the electrode lifetime. For example, in the electrolytic copper foil production, IrO₂-Ta₂O₅/Ti anodes are used for oxygen evolution in acidic electrolyte solutions. Although copper sulfate electrolyte is used for this process, Pb (II) ions can be found as an impurity in the solution. During operation lead oxidation is a side reaction leading to PbO₂ electrodeposition on the electrode surface. The deposited PbO₂ can be further reduced to a non-conductive PbSO₄ layer, increasing cell voltage over time.

Typical fabrication of IrO₂-Ta₂O₅/Ti electrodes includes thermal deposition at high temperatures about 450-500 °C. Material characterization techniques revealed that the catalytic layer is composed of crystalline IrO₂ and amorphous TaO₂. Also, segregated IrO₂-Ta₂O₅ particles were found on the surfaces along with flat areas and cracks. Therefore, it is very important to elucidate the key parameters to obtain a more homogeneous catalyst since it has been proved that surface morphology has a direct impact on electrocatalytic activity.

Recent efforts in the study of IrO₂-Ta₂O₅/Ti electrodes were presented by Kawaguchi and Morimitsu, they investigated the effect of the thermal decomposition temperature on both the surface morphology and the electrocatalytic activity of the resulting electrodes (Kawaguchi & Morimitsu, 2020). The experiments were conducted at different temperatures (470 and 380 °C) and IrO₂/Ta₂O₅ ratios. The results showed that at low temperature a nano/amorphous hybrid structure of IrO₂ particles was created. The nanoparticles were highly dispersed in an amorphous Ta₂O₅ matrix. Regarding the electrocatalytic activity, the oxygen evolution was accelerated with an increasing Ir ratio at the low temperature. Moreover, anodic PbO₂ deposition was completely suppressed even in the presence of an electrolytic solution containing 100 ppm PbSO₄ in acidic conditions. On the other hand, the PbSO₄ deposition on electrodes fabricated at 470 °C was confirmed.

Studies like the one of Kawaguchi and Morimitsu can help to improve the overall performance of Ti-coated electrodes at the industrial scale. However, these electrodes need further improvement regarding durability. Nevertheless, the study sets a precedent for future investigations.

Watch the discussion of this paper in our weekly science review:

For more details on this study, please refer to the full articles available at https://iopscience.iop.org/article/10.1149/1945-7111/abb7e8.

Kawaguchi, K., & Morimitsu, M. (2020).  Reaction Selectivity of IrO 2 -Based Nano/Amorphous Hybrid Oxide-Coated Titanium Anodes in Acidic Aqueous Solutions: Oxygen Evolution and Lead Oxide Deposition. Journal of The Electrochemical Society, 167(13), 133503. https://doi.org/10.1149/1945-7111/abb7e8

Great efforts have been put in the development of new strategies to stabilize Li and Zn anodes. To do this, several materials like graphene, carbon nanotubes, porous copper, and graphite filters have been used to control de lithium ion deposition. The utilization of porous material reduces the local current densities helping to increase battery life. Another strategy is based on the use of structured electrolytes containing immobilized anions to stabilize the electrodeposition in metal anodes at large overpotentials. These structures are used between the electrode and the separator to allow a more homogeneous plating on the electrode surface.

The latter strategy was explored recently by Zhi et al, they proposed the use of collagen hydrolysate (CH) coated on an adsorbed glass mat (AGM) substrate (Zhi et al., 2020). CH-AGM is used as an interlayer to produce a phenomena called shock electrodeposition to stabilize the metal anode and suppress dendrite growth. In this case, the negative charge on the surface of the CH-AGM interlayer is caused by oxygen functional groups in the backbone of the collagen hydrolysate. The authors tested the CH-AGM interlayer in full cells with Li and Zn anodes at different scales from 5, 65, and 200 Ah. The implementation of the CH-AGM in the full cells resulted in outstanding performance, both the Li and Zn batteries delivered up to 600 cycles with a coulombic efficiency of 99.7 %. While pristine Li and Zn batteries failed after 10 and 100 cycles, respectively. According to the authors, the cells containing CH-AGM present a cation regulation mechanism which can simultaneously induce an ionization shock within the separator and spread cations on the anode surface to perform homogeneous plating.

The development of novel strategies to overcome fundamental challenges related to dendrite growth, fast metal depletion, and electrode passivation is required, especially for high loading intercalation cathodes. The use of biomaterials such as collagen can have a great impact with a relatively easy fabrication procedure like the one presented by Zhi et al. The promising results of obtained in their work indicate the possibility to increase the stability of the batteries in a simple and efficient way.

Watch the discussion of this paper in our Weekly Science Review below.

For more details on the work of Zhi et al, please refer to the full paper available at https://advances.sciencemag.org/content/6/32/eabb1342/tab-pdf.

Zhi, J., Li, S., Han, M., & Chen, P. (2020). Biomolecule-guided cation regulation for dendrite-free metal anodes. Science Advances, 6(32), 1–15. https://doi.org/10.1126/sciadv.abb1342

Conversely to hydrogen fuel cells, where the limiting factor is the cathode, the energy conversion efficiency of DMFCs is limited by the methanol oxidation reaction (MOR) at the anode. The current benchmark catalyst for MOR is Pt, however, it suffers from CO poisoning decreasing its performance after just a few cycles.

Pt-alloys catalyst can pave the way toward more efficient devices, therefore most of the research have been focused in the study of Pt alloys. Among the alloys used as anode materials for DMFCs, we can find those formed with Ru and Rh. PtRu alloys have been proved to possess a better catalytic activity for MOR, however, its activity under acidic conditions lack of stability. Other studies have shown that PtRh alloys can help to break C-C bonds, increasing the stability of the electrodes avoiding typical CO poisoning affecting Pt catalyst.

Recently, a study performed by Shi et al at the Nanjing Normal University explored the effect of the fabrication method over the performance of both PtRu and PtRh alloys (Shi et al., 2020). The hydrothermal method used in this work allow the monodisperse PtRu and PtRh alloys on carbon substrate such as Vulcan. Then both catalysts where tested under acidic conditions for electrochemical characterization by cyclic voltammetry for 300 cycles.

The implementation of the facial hydrothermal technique used by Shi et al, allowed the formation of nanoparticles with an average diameter of 2.3 nm. During testing, PtRh/C catalyst showed an increase in current density during the first 80 cycles. After the 80^th cycle, a slight decrease in current density was observed. The enhanced and further decay in the performance of the PtRh/C electrode was attributed to the exposure of the Pt catalyst. Despite the decrease in the catalytic activity, the Rhodium tend to be stable and reaches a relatively stable performance. On the contrary, ruthenium catalyst showed less stability with a decreased performance after only 39 cycles.

Studies like that performed by Shi et al can help to understand the electrocatalytic activity of MOR process in acid. For this process it is important to develop analytical protocols to follow evolution of catalyst in composition and structure.

Watch the discussion of this paper in our Weekly Science Review:

For more details please refer to full article is available at https://www.sciencedirect.com/science/article/pii/S1388248120300412#b0075.

Shi, Z., Li, X., Li, T., Chen, Y., & Tang, Y. (2020). Evolution of composition and structure of PtRh/C in the acidic methanol electrooxidation process. Electrochemistry Communications, 113(January), 106690. https://doi.org/10.1016/j.elecom.2020.106690

To this date Pt and Pt-based materials are known as the best catalysts for ORR, however, these materials often suffer from easy poisoning and are very expensive. Therefore, it is of great interest to develop new electrocatalysts with high efficiency and low cost. In the search for a novel catalyst, the production of highly efficient electrocatalyst based on rich earth elements has become a common practice.

Novel materials such as Metal-Organic Frameworks (MOFs) have been raised as a promising element for the fabrication of catalyst. MOFs are highly ordered structures consisting of a metal center bridged together by organic ligands. These novel materials can be used as precursors for the fabrication of carbon-based materials. Their attractive properties include a super-high surface area, high thermal and chemical stability, high reactivity, and relatively easy fabrication.

To better understand the process of ORR, it is important to explore the effect of active components such as transition metals. Based on theoretical estimations, Cu-based catalysts can have higher activity than others like Fe, Co, Ni, etc. The major drawback of Cu-based materials is their reduced chemical and thermal stability, and poor conductivity. Recent research has been done for the generation of Cu, carbon, or nitrogen nanostructures which can be used for the fabrication of catalysts for ORR.

An example of the combination of these materials and techniques can be found in the study presented by Parkash at Shaanxi Normal University. He proposed the fabrication of Cu promoted nitrogen-doped carbon based on Cu/ZIF-8 MOF (Parkash, 2020). The synthesis of the novel catalysts has as final step pyrolysis under an inert atmosphere of nitrogen, this step proved to be determinant on the electrocatalytic activity of the material. The pyrolysis step was carried out using temperatures of 500, 600, 700, 800, and 900 °C. The results showed that the catalyst fabricated at 800 °C has an outstanding electrocatalytic activity in basic media and exhibited higher stability compared to the Pt/C catalyst. According to the author, the impressive catalytic bifunctional performance can be attributed to the strong synergy between Cu (II)-N ligands and Cu⁰ nanoparticles, rich active centers, and rapid mass transfer. Also, after the accelerated aging test, the catalyst retained its activity even after 1000 cycles, this demonstrates the high stability achieved through the fabrication process based on the ZIF-8 MOF.

Similar studies need to be conducted to understand the mechanism associated with ORR. Metal-N co-doping strategy will significantly improve the catalyst’s electrocatalytic operation, which provides a valuable guideline for the design of a new non-noble N-doped carbon-based ORR catalyst. This work will promote the development of effective, low cost, nanostructured non-noble metal electrocatalysts for renewable energy conversion and storage.

Watch the discussion of this paper in our weekly science review below.

For more details please refer to the full paper available at https://iopscience.iop.org/article/10.1149/1945-7111/abaaa5

Parkash, A. (2020). Copper Doped Zeolitic Imidazole Frameworks (ZIF-8): A New Generation of Single-Atom Catalyst for Oxygen Reduction Reaction in Alkaline Media. Journal of The Electrochemical Society, 167(15), 155504. https://doi.org/10.1149/1945-7111/abaaa5

The determination of serotonin can be carried out in urine and serum, and several analytical methods are currently employed including High-Performance Liquid Chromatography (HPLC), fluorimetry, mass spectrometry, enzyme-linked immune sorbent assay (ELISA), and electrochemical methods. Among these methods, an electrochemical determination is considered the best option using simple procedures like cyclic voltammetry and differential pulse voltammetry. For this matter, electroanalytical techniques have proved to be an effective, painless, and low-cost method for quick diagnosis.

The implementation of nanomaterials has attracted attention in the field of sensors, allowing to increase the sensitivity and stability of sensor devices. Electrochemical sensors require stable materials in different conditions of pH and temperature. Typical construction of the working electrode consists of the functionalization of a carbon-based material with nanomaterials containing metals, metal oxides, metal sulfide, etc. Among metal oxides, ZrO₂ (zirconia) is a very prominent material possessing high stability and hardness at high temperatures.

In a recent report, Bullapura et al explored the use of ZnO₂ nanoparticles (ZnO₂-NPs) for the electrochemical detection of serotonin (Bullapura Matt et al., 2020). In this work, an easy method for the fabrication of the nanoparticles consisted of a gel-combustion method. The formation of nanoparticles was confirmed by SEM and TEM analysis, ZnO₂-NPs showed an average particle size of 40 nm. After the synthesis, the zirconium nanoparticles were added to a carbon paste electrode.

During the electrochemical characterization, the carbon paste electrode with the ZnO₂-NPs showed improved catalysis towards serotonin in comparison to the bare carbon material. To identify the effect of pH on the catalytic activity, the authors performed the determination at different pH values in the range of 6.2-7.4. The maximum electrocatalytic activity was found at 7.4 which is also physiological pH, this fact indicates that serotonin determination can be carried out without sample pretreatment. The interferences were evaluated versus dopamine, in this case, the differential pulse voltammetry technique help to separate the contribution of each molecule and no interference was found. The method proposed by Bullapura et al showed to be highly sensitive allowing the determination of serotonin in concentrations of 10-50 µM with a limit of detection of 0.585 µM.

The implementation of novel materials at the nanoscale can help to increase the sensitivity, selectivity, and stability of electrochemical sensors for the detection of different molecules of interest for medical applications.

Watch the discussion of this paper in our weekly science review:

For more details of this study, please refer to the full article available at https://iopscience.iop.org/article/10.1149/1945-7111/abb835

Bullapura Matt, S., Shivanna, M., Manjunath, S., Siddalinganahalli, M., & Siddalingappa, D. M. (2020).  Electrochemical Detection of Serotonin Using t-ZrO 2 Nanoparticles Modified Carbon Paste Electrode. Journal of The Electrochemical Society, 167(15), 155512. https://doi.org/10.1149/1945-7111/abb835

Currently, metal oxide-based sensors are the preferred technology, however, several drawbacks limit their application. Metal oxide-based sensors often suffer from easy poisoning, limiting their sensitivity. Also, they require long recovery periods and operate at high temperatures. Owing to their unique properties, nanomaterials are considered promising prospects for sensing applications. For instance, graphene and graphene-based nanomaterials have shown improved sensitivity due to the large specific surface area, fast electron kinetics, and strong surface activities.

In the search for highly sensitive and portable sensors that work at low temperatures, several new materials have been raised including MoS₂. Two-dimensional layered MoS₂ is very attractive for gas sensing applications due to their high surface-to-volume ratio, high surface activities, and sensitivities, along with their good stability and fast response time. The suitable and tunable bandgap energies in MoS₂ materials makes them more desirable than graphene for gas sensing applications.

Recently, Chacko et al reported a study exploring the use of different MoS₂ materials such as pure MoS₂, MoS₂-ZnO, MoS₂-Ni, and MoS₂-Pd for the fabrication of sensor devices (Chacko et al., 2020). The sensors were exposed to NO, NO₂, NH₃, and H₂S gases, and their selectivity, sensitivity, and repeatability were assessed. The results showed that the Pd-MoS₂ layers exhibited a very high relative response to NO gas (700%) at 2 ppm concentration with a detection limit of 0.1 ppm. Ni-MoS₂ showed a relative response of 80% towards H₂S gas with a limit of detection of 0.3 ppm. According to the authors, the good repeatability and selectivity of both sensors are related to the increased adsorption energy of NO on Pd-MoS₂ and H₂S on Ni-MoS₂ through the formation of PdNOx and NiS₂ complexes respectively.

The exploration of MoS₂ materials can help to meet the requirements of real sensing applications such as high sensitivity, limited cross-sensitivity, multi-component capability, and fast response time. Different studies have demonstrated that the application of MoS₂ materials is not limited to gas sensors for pollution control, they also can be used for the fabrication of biosensors (DNA sensors) for the detection of cancer biomarkers.

Watch the discussion of this paper in our Weekly Science Review:

For more details please refer to the full article that is available at https://iopscience.iop.org/article/10.1149/1945-7111/ab992c

Chacko, L., Massera, E., & Aneesh, P. M. (2020).  Enhancement in the Selectivity and Sensitivity of Ni and Pd Functionalized MoS 2 Toxic Gas Sensors. Journal of The Electrochemical Society, 167(10), 106506. https://doi.org/10.1149/1945-7111/ab992c

Redox Flow Batteries are electrochemical devices that store energy using chemicals as energy carriers which are usually found in liquid form. The cell is separated by a selective membrane (usually a proton exchange membrane) to avoid loss of capacity due to cross-mixing. The liquids containing the redox-active species are pumped to the cell during charge/discharge cycles. In the scientific literature, we can find a wide variety of chemistries and configurations for RFBs. However, iron-based flow batteries are commonly used due to the low cost of active redox materials, availability, and environmental friendliness.

The energy storage capacity and energy density of RFBs rely on several factors, for instance, the cell voltage is dependent on the redox potential of the half-cell reactions. Typical cell voltages range from 1 to 2.4 V. The storage capacity is dependent on the concentration of the redox species, higher concentrations mean higher capacity. Despite the advantages of iron-based RFBs, some challenges remain regarding long-term chemical stability and durability. Since the iron species are dissolved in aqueous solutions, parasitic reactions such as hydrogen evolution can limit the performance and life of the battery.

Low-cost iron sources can be found in the industry, for example, steel mills generate enormous amounts of iron sulfate as waste. Taking advantage of such materials can be beneficial for energy storage systems. In a recent study, Yang et al at the University of Southern California proposed an innovative RFB based on iron sulfate and an organic molecule (anthraquinone disulfonic acid-ADQS) having a relatively low cell voltage of 0.62 V (Yang et al., 2020).

Another major challenge for RFBs is the species cross-over through the proton exchange membrane (PEM), which is considered one of the related issues to capacity fade. Most RFBs are operated in an asymmetrical mode, where one species is used for anodic reactions while another is used for the cathode. The exploration of other operation modes can help to understand capacity loss and improve durability. In the work presented by Yang et al, the authors proposed the operation in a symmetrical mode, where both electrolytes were mixed in separated tanks for the positive and negative electrolytes. According to the authors, despite that the species are mixed in the solution, selective reactions are taking place at each electrode. The results proved that in such a mode, over 500 cycles can be achieved with a negligible capacity fade of 7.6 × 10^-5 % per cycle with sustained coulombic efficiency of 99%. Despite the lower cell voltage in comparison with other chemistries, this alternative can help to meet the requirements of cost, durability, and scalability for large scale applications.

Watch our discussion of this paper in our Weekly Science Review:

For more details, please refer to the full article available at: https://iopscience.iop.org/article/10.1149/1945-7111/ab84f8

Yang, B., Murali, A., Nirmalchandar, A., Jayathilake, B., Prakash, G. K. S., & Narayanan, S. R. (2020). A Durable, Inexpensive and Scalable Redox Flow Battery Based on Iron Sulfate and Anthraquinone Disulfonic Acid. Journal of The Electrochemical Society, 167(6), 060520. https://doi.org/10.1149/1945-7111/ab84f8

Current technology for Au recovery is based on hydrometallurgical treatments, however, this process is both time-consuming and generates hazardous liquid wastes. Due to the chemical inertness of gold, a combination of strong complexing and oxidation agents is necessary. The most common combinations for Au dissolution include cyanide/hydrogen peroxide, hydrochloric acid/chlorine, hydrochloric acid/hydrogen peroxide, and hydrochloric acid/nitric acid. Furthermore, waste PCBs contain several components making more difficult the separation of gold, requiring a series of complex steps.

Owing to the disadvantages of hydrometallurgical methods, more simple and environmentally friendly processes are required for the recovery of gold. The implementation of electrochemical methods for the recovery of different metals is well-documented. Typically, electrodeposition is carried out when the metal is deposited in the cathode (cathodic deposition). In such a case, the transient metals are found as cations (M⁺) in ionic solutions, and the cation is reduced to metal (reduction reaction: Mn⁺ + n e^– → M).

Alternatively, anodic deposition has been used in a few cases for metals such as Pb, Sb, and Au. In a recent report, Ouchi et al from the University of Tokyo proposed the use of anodic deposition of gold that has been dissolved in molten salts (Ouchi et al., 2020). The dissolution of metals in the anionic form is achieved by generating an alloy with a reactive metal with low electronegativity such as Na. Once the Au is dissolved in the molten salt, a graphite rod and a Mo rod were immersed in the molten salt and function as anode and cathode, respectively. Then the anodic deposition was conducted by applying a constant potential, the gold is deposited on the anode and the sodium on the cathode. After the deposition step, the presence of gold was confirmed by analytical techniques as Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD).

The method proposed by Ouchi et al offers several advantages, for instance, no hazardous wastes are generated. Sodium can be reused in the process and no side reactions are present as the generation of Cl_2(g) in other electrochemical methods. Furthermore, in comparison with conventional technologies, anodic deposition can reduce the time and simplify the process.

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For more details, please refer to the full paper available at

https://iopscience.iop.org/article/10.1149/1945-7111/aba6c5

Ouchi, T., Wu, S., & Okabe, T. H. (2020). Recycling of Gold Using Anodic Electrochemical Deposition from Molten Salt Electrolyte. Journal of The Electrochemical Society, 167(12), 123501. https://doi.org/10.1149/1945-7111/aba6c5