Volker
Presser
INM – Leibniz Institute for New Materials, 66123 Saarbrücken, Germany. E-mail: volker.presser@leibniz-inm.de
• In the realm of photoelectrochemical cells, two-dimensional (2D) materials have proven revolutionary, offering unique electronic and mechanical properties distinct from their bulk counterparts. The review “Two-dimensional materials for photoelectrochemical water splitting” by Jun et al. explores 2D materials to enhance unassisted solar water splitting by integrating their unique characteristics into semiconducting photoabsorbers. It highlights the intrinsic advantages of 2D materials, such as transition metal dichalcogenides, graphene, graphdiyne, black phosphorus, layered double hydroxides, and MXenes, all of which are pivotal in improving the photoelectrochemical performance of photoelectrodes. The paper emphasizes the potential of carefully constructed heterostructures combining photoabsorbers with 2D materials for efficient light harvesting and hydrogen and oxygen evolution. It concludes with a discussion on the future outlook, focusing on developing synthetic technologies for mass production, enhancing stability, and building tandem architectures for unbiased solar water splitting [https://doi.org/10.1039/D2YA00231K].
• The review article “Defect engineering in antimony selenide thin film solar cells” by Wijesinghe et al. focuses on antimony selenide (Sb2Se3), an emerging inorganic absorber in thin-film photovoltaics and water splitting devices, recognized for its excellent optoelectronic properties, low toxicity, and abundance. Despite achieving a record power conversion efficiency of 10.12%, further efficiency improvements in Sb2Se3 solar cells are challenged by open circuit voltage deficits due to defects and interfacial recombination. These defects impact charge carrier generation, transportation, intrinsic electrical conductivity, and film crystallinity, thus affecting the efficiency and stability of the cells. The paper comprehensively reviews defect chemistry in Sb2Se3 solar cells, focusing on surfaces, grain boundaries, interfaces, and community efforts in defect passivation. It concludes with potential challenges and strategies for developing highly efficient and stable Sb2Se3 solar cells [https://doi.org/10.1039/D2YA00232A].
• The communication paper by Ugata et al. entitled “Improved reversibility of lithium deposition and stripping with high areal capacity under practical conditions through enhanced wettability of the polyolefin separator to highly concentrated electrolytes” focuses on the development of an enhanced separator for lithium metal batteries using highly concentrated electrolytes (HCEs), which are known for improving the reversibility and cycling performance of lithium metal negative electrodes. The research addresses the challenge of poor wettability in conventional polyolefin separators when used with HCEs. The team reports that using a meta-aramid-coated polyolefin separator significantly improves wettability due to its polar surface functional groups. This innovation enables stable and dendrite-free lithium deposition and stripping, achieving a high Coulombic efficiency of approximately 98% at a practical areal capacity of 2 mA h cm−2 over 100 cycles. This advancement, combining HCEs with functional separators, holds promise for developing practical lithium metal batteries [https://doi.org/10.1039/D2YA00359G].
• Cai and Koenig have presented in their work “Enhancing low electronic conductivity materials in all active material electrodes through multicomponent architecture” a novel approach in lithium-ion battery technology exploring the use of “all active material” (AAM) electrodes, which are composed solely of electroactive materials that have been mechanically compressed and mildly thermally treated to create a porous electrode pellet. The focus is on integrating a material with high gravimetric capacity but low electronic conductivity, specifically LiNi0.5Mn0.5O2 (LNMO), into an AAM cathode. The study addresses the issue of high polarization in LNMO due to its low electronic conductivity by blending it with LiCoO2 (LCO), a material with higher electronic conductivity but lower gravimetric capacity. This combination forms a multicomponent AAM cathode, where the LCO/LNMO blend shows improved electrochemical properties. The enhancement is attributed to LCO forming a percolated network for electron transport while maintaining segregation between LCO and LNMO particles in the electrode structure. The paper presents a new concept in incorporating materials with relatively low electronic conductivity into AAM electrodes, utilizing a multicomponent architectural approach, with outcomes analyzed through pseudo-two-dimensional simulations of cell cycling [https://doi.org/10.1039/D2YA00269H].
• The paper of Srivastava et al. “Effect of Ti1−xFexO2 photoanodes on the performance of dye-sensitized solar cells utilizing natural betalain pigments extracted from Beta vulgaris (BV)” explores the enhancement of dye-sensitized solar cells (DSSCs) using naturally occurring dyes, specifically focusing on the performance and stability of these cells with engineered photoanodes. Fe-doped TiO2 nanorods (NRs) were synthesized on fluorine-doped tin oxide (FTO) electrodes using a hydrothermal method. The research examined the effects of varying concentrations of Fe in Ti1−xFexO2 photoanodes on their physicochemical and electrical characteristics. Utilizing a natural dye extracted from Beta vulgaris (BV), the study demonstrated a significant improvement in the photovoltaic performance of DSSCs. Including 5 at% Fe in TiO2 NRs increasing photocurrent density from 80 to 129.758 μA cm−2 and doubling the power conversion efficiency (PCE) from 0.26% to 0.52%. This improvement is attributed to enhanced charge injection and separation by the Ti1−xFexO2 interlayer. The results suggest that such photoanodes, with their improved responsiveness, could surpass pure TiO2 nanostructures in photovoltaic applications and also show promise for use in photocatalysis and photo sensors [https://doi.org/10.1039/D2YA00197G].
My personal 2023 highlight, among many excellent works, was the perspective written by Knehr et al. “From material properties to device metrics: a data-driven guide to battery design” [https://doi.org/10.1039/D3YA00137G]. This paper offers a data-driven analysis of the key factors influencing battery performance, including material parameters, cell design choices, and manufacturing costs, and how they impact crucial battery metrics like energy, power, cost, lifetime, and safety. Utilizing Monte Carlo simulations of lithium-ion batteries through the Battery Performance and Cost (BatPaC) model from Argonne National Laboratory, the study identifies the most critical parameters for optimizing each metric. It also explores the potential trade-offs required to achieve multiple objectives, such as high energy density and extended battery life, providing valuable insights for designing and developing more efficient and sustainable battery technologies.
• Blue and green hydrogen production & storage
• Flowable energy storage
• High entropy energy materials
• AI & ML in energy storage and conversion
The Emerging Investigator Series is particularly dear to us, where we showcase the exciting research our fantastic early-career community conducts. So far, the research topics in this series include amorphous MOFs for next-generation supercapacitors and batteries [https://doi.org/10.1039/D3YA00306J], 2D–2D heterostructure hybrids for efficient electrocatalysis [https://doi.org/10.1039/D2YA00318J], computational approaches for rapid metal site discovery in carbon-based materials for electrocatalysis [https://doi.org/10.1039/D3YA00321C], photothermal catalytic Cl conversion on supported catalysts [https://doi.org/10.1039/D3YA00315A], anodic dissolution of aluminum in non-aqueous electrolyte solutions for sodium-ion batteries [https://doi.org/10.1039/D3YA00233K], and the reversible alkaline hydrogen evolution and oxidation reactions using Ni–Mo catalysts supported on carbon [https://doi.org/10.1039/D3YA00140G].
Let's continue to advance energy in 2024 and beyond!
Prof. Dr Volker Presser, FRSC
Editor in Chief, Energy Advances
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