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Electrochemical CO₂ reduction (ECCO₂R) is a viable and promising approach for converting the greenhouse gas carbon dioxide into useful chemicals and fuels. Electrochemical activity and product selectivity are essential for this purpose. The ECCO₂R can lead to the formation of a wide variety of by-products, which is primarily dictated by the nature of electrocatalysts. Surface modification of electrocatalysts with oxide and/or hydroxide moieties can be a simple yet effective strategy to improve activity and selectivity of the ECCO₂R process. This article attempts to review and identify relationship between the surface hydroxylation of electrocatalysts and the product selectivity. Impact of electrocatalyst’s surface modification with oxide/hydroxide on activity, product selectivity, intermediate stability, plausible mechanism and catalyst evolution during the ECCO₂R is highlighted by focusing on select and representative research findings. The review finds that the product selectivity is highly dependent not only on the presence of OH group on the electrocatalysts' surfaces but also the type and distribution of the group. Moreover, the selectivity can be tuned by introducing and controlling the density of surface OH. Future perspectives and challenges are also emphasized.

The scale-up of supercapacitors by electrophoretic deposition (EPD) from coin cell to pouch cell with commercially relevant mass loadings and thicknesses is reported. The use of EPD in electrode fabrication mainly reduces the interfacial resistance and increases the mechanical flexibility of the electrodes. The cycling performance or conversion efficiency can also be improved due to the highly porous EPD coatings. An exemplary investigation of activated carbon (AC) electrodes with an electrolyte comprising of tetraethylammonium tetrafluoroborate in acetonitrile is carried out. According to the general literature, EPD of AC on metal substrates has not performed well for supercapacitor electrodes unless they were thinner and with lower mass loadings than commercial requirements. As a consequence, and to redress this research gap, all the electrodes prepared in this work demonstrate high mass loadings (8 mg cm⁻²) and practical layer thicknesses (125 µm) and contain polyvinylidene fluoride binders with electrically conductive carbon black particles. Research investigations include: (a) impact of EPD of AC onto small (10 cm²) and large areas (50 cm²) of aluminum foil current collectors, (b) scaling-up of coin to pouch cells, and (c) the preparation of electrode coatings on both sides of the current collector for the first time using EPD for pouch cell investigations. Our research learning shows the evidence of practical cell performance, including current loading (40 A g⁻¹), tens of thousands of successive charge and discharge operation (150,000 cycles), power (30 kW kg⁻¹) and energy densities (10 W h kg⁻¹), capacitance (154 F g⁻¹), capacitance retention (80%) and coulombic efficiency (relatively close to 100%). Based upon the success of the pouch cells investigated in this work, further research studies on the use of EPD for preparing energy storage electrodes for commercial cylindrical types of supercapacitors is envisaged.

The development of graphene-based electrodes for application in energy storage and energy harvesting devices represents an important strategy for producing wearable devices with requisites of flexibility and good electrochemical performance. Herein, the use of laser-induced graphene (LIG) has been explored as a simple and efficient method for the production of interdigitated microsupercapacitors (μSCs) and back electrodes for triboelectric nanogenerators (TENGs) active layers by direct production of graphene from Kapton polyimide and by the transference of the pattern to polydimethylsiloxane (a typical tribonegative layer for TENG). An open circuit voltage of 189.7 V, short circuit current of 39.8 μA, and power of 302.5 μW (power density of 20.2 μW/cm²) was observed for the conventional TENG while an areal capacitance of 2.5 mF/cm² with good retention in the energy generation and cyclability in energy storage was observed for the microsupercapacitor. The most relevant aspect to be considered is a single-step method for transference of back-electrode to the Poly(dimethylsiloxane) requiring minimal processing steps for morphology control in the friction layer and self-powered behavior for integration of TENG/microsupercapacitor in a power unit cell.

Humidification of polymer electrolyte membranes in fuel cells is essential for high proton conductivity and lifetime, therefore often membrane humidifier modules are used. We report about the degradation of polyimide humidifier membranes under the influence of airborne ozone traces: during operation we tracked the membranes humidifier performance in 5 modules for up to 1000 h with trace levels of ozone (100 ppb) and conducted characterization tests at 200 h intervals. Operating the humidifier with ozone resulted in a linear decrease in the membrane's ability to transfer moisture over time. Moreover, the glass transition temperature of the membrane material decreases linearly with longer exposure to ozone, while the mechanical strength in terms of breaking force and elongation at break decreases too. Infrared spectra of the tested fibers showed no changes. The reduced water vapor flux would limit fuel cell performance, while the reduced mechanical properties of the membrane can lead to rupture.

Benefiting from the advantageous features of low manufacturing cost, inherent safety and resource renewability, aqueous Zn-ion batteries (AZIBs) are considered as one of the most promising candidates for energy storage systems. Unfortunately, problems of AZIBs such as cathode dissolution, Zn dendrite growth, and irreversible electrochemical side reactions have restricted the implementation for practical applications. Vanadium-based are deemed as hopeful cathode materials for AZIBs owing to diverse crystal structures and multiple valence states. Therefore, it is necessary to comprehensively summarize the advance facing vanadium-based cathodes and the corresponding progress to create roadmaps for the development of high-stability AZIBs. This review starts with a discussion of the storage and failure mechanisms of AZIBs and their related affects. Then, enormous up-to-date achievements of vanadium-based cathode materials are highlighted, including vanadium-based oxides and metal vanadium-based oxides. The challenges associated with the application of vanadium-based compounds in AZIBs are also highlighted, and effective strategies to overcome them are proposed. Finally, perspectives and directions on further optimizing vanadium-based cathode materials to improve the performance of AZIBs are discussed.

Severe capacity degradation at high operating voltages and poor interphase stability at elevated temperature have thus far precluded the practical application of LiNi_0.5Mn_1.5O₄ (LNMO) as a cathode material for lithium-ion batteries. Addressing these challenges through a combination of experimental and theoretical methods in this work, we demonstrate how a fluorinated carbonate electrolyte enables both high-voltage and high temperature operation by mitigating the traditional interfacial reactions observed in electrolytes with conventional carbonate solvents. Computational studies confirm the exceptional oxidation stability of fluorinated carbonate electrolyte which reduces deprotonation at high voltage. The mitigated deprotonation will then minimize the formation of HF acid which corrodes the LNMO surface and leads to phase transformation and poor interphases. With fluorinated carbonate electrolyte at elevated temperature, it was found on LNMO’s subsurface a reduced amount of Mn₃O₄ phase which can block Li⁺ transfer and result in drastic cell failure. Leveraging this approach, LNMO/graphite full cells with a high loading of 3.0 mAh/cm² achieve excellent cycling stability, retaining ∼84 % of their initial capacity at room temperature (25 °C) after 200 cycles and ∼68 % after 100 cycles at 55 °C. This advanced electrolyte also shows promise for improving calendar life, retaining >30 % more capacity than the carbonate baseline after high temperature storage. These results indicate that electrolytes based on fluorinated carbonates are a promising strategy for overcoming the remaining challenges toward practical commercial application of LNMO.

Energy resilience is a vital consideration for ensuring the survivability of modern infrastructure systems. Achieving 100% resilience, however, is often impractical and economically burdensome. In this paper, we propose a smart investment framework that enables decision-makers to determine optimal investments in energy resilience based on available resources and desired levels of resilience. To illustrate the effectiveness of this framework, we present a case study of a campus microgrid research and testing facility. Using a real-time simulation approach conducted with Typhoon Hardware In Loop (HIL), we evaluate the performance of the microgrid system over 24 hours following 4 historically significant hurricanes that have affected Louisiana in the past few years. The microgrid is designed to power local loads during outages, providing an effective solution for enhancing energy resilience. Real solar data collected from our 1.1 Megawatt (MW) solar facility on the University of Louisiana at Lafayette campus is integrated into the simulation, enabling a realistic evaluation of the system’s performance under hurricane-induced disruptions. By employing the proposed smart investment framework, decision-makers can better identify and address resilience challenges. The framework facilitates informed investment decisions by considering available resources and aligning them with the desired level of resilience. This approach avoids over-investment in unnecessary redundancy while ensuring critical systems are adequately protected. Our research contributes to the field by demonstrating the practicality and benefits of a smart investment framework for energy resilience in a real-world scenario. The case study of the campus microgrid research facility provides valuable insights for decision-makers in similar contexts, highlighting the potential of this framework to guide resilient energy infrastructure planning and investment strategies.

This work focuses on a very narrow region in the quaternary system Na₂O-P₂O₅-SiO₂-ZrO₂ to explore the occasionally proposed deficiency in zirconium and oxygen content of Na⁺ super-ionic conductor (NaSICON) materials. In addition, this region is known for the formation of glass-ceramics, but a systematic study of such materials has not been carried out yet. For this purpose, 2 series of compositions were defined and synthesized: Na_3.4Zr_2-3x/4Si_2.4-x/4P_0.6+x/4O_12-11x/8 and Na_3.4Zr_2-3x/4Si_2.4+x/4P_0.6+1.5x/4O_12-x/16. They only differ in the silicate and phosphate content. In the first series the molar content is constant, n_Si + n_P = 3. The latter series allows an excess of the 2 cations to meet the composition Na_3.1Zr_1.55Si_2.3P_0.7O₁₁ or alternatively re-written as Na_3.4Zr_1.7Si_2.52P_0.77O_l2, which was formerly regarded as a superior material to the frequently reported composition Na₃Zr₂Si₂PO_l2.

Several characterization techniques were applied to better understand the relationships between phase formation, processing, and properties of the obtained glass ceramics in the context of the quasi-quaternary phase diagram. The investigations gave clear evidence that a glass phase is progressively formed with increasing x. Therefore, compounds with x > 0.2 have to be regarded as glass-ceramic composites. The resulting NaSICON materials revealed a very limited Zr deficiency with charge compensation by Na ions and a non-detectable amount of oxygen vacancies verified by neutron scattering and atomistic simulations.

Hence, this work is the first systematic investigation of pretended Zr-deficient NaSICON materials, which clearly show the chemistry of a 2-phase region. The 2 investigated series are directed toward a region that is orthogonal to the series Na₃Zr_3-ySi₂P_yO_11.5+y/2 reported in the first part of this series of publications.

The electrode is a core component that affects the overall performance of the hydrogen/iron redox flow battery. To address the drawbacks associated with the limited electrochemical activity and fewer active sites of the carbon-based electrode, this study employs a straightforward and effective flame method to synthesize carbon nanotubes (CNTs) on carbon paper and NiO/CNT composite on graphite felt. The CNT on the modified carbon-based electrode contains many hydrophilic and oxygen-containing functional groups, greatly improving the hydrophilicity of the electrode, thereby increasing the electrochemical surface area. The modified carbon-based electrode exhibits better electrochemical activity due to the CNT or NiO/CNT providing more active sites. At 50 mA cm⁻², the energy efficiency of pristine carbon paper and graphite felt is 60.8% and 52.4%, respectively, while the energy efficiency of the modified carbon paper and graphite felt reached 75.3% and 80.5%, respectively. The modified carbon-based electrode achieves a 100% coulombic efficiency, with no significant degradation in energy efficiency after running for 300 cycles, demonstrating excellent stability. This study not only investigates the performance of graphite felt electrodes in hydrogen/iron batteries but also proposes a flame method for preparing CNT-modified carbon-based electrodes for high-performance hydrogen/iron batteries.

Small Modular Nuclear Reactors (SMRs) offer a promising option for environmentally friendly bitumen recovery operations. The extraction of oil sands in Western Canada is vital for the economy, but traditional methods like Steam-Assisted Gravity Drainage (SAGD) contribute significantly to greenhouse gas (GHG) emissions. In SAGD, steam generation, primarily fueled by natural gas combustion, is the main source of emissions. Given the imperative to reduce carbon intensity, less emissive recovery methods are needed to sustain production and economic viability in Canadian oil sands. Currently, there are limited non-carbon alternatives for steam generation in oil sands applications. The utilization of SMRs for steam generation presents a clean alternative. In this study, we examine the feasibility of employing SMRs in in-situ oil sands recovery operations. Through standardized economic metrics and sensitivity analysis, we demonstrate that integrating SMRs into SAGD operations eliminates GHG emissions significantly and can potentially outperform conventional natural gas-based steam generation in terms of net present value, under certain operational scenarios. Hence, our findings indicate that SMRs hold promise for decarbonizing oil sands recovery processes.