Exploring the Potential of Solution-Based Synthesis Towards Material- and Energy-Efficient Oxide Electrodes for Future Energy Storage

The ongoing transition from fossil-based to renewable energy sources and the imperative for a carbon-neutral economy are driving research and industry to reassess material choices as well as synthesis methodologies.<br/><br/>Multi-metal oxides, particularly within the domain of oxide electrodes play a crucial role in renewable energy storage applications, including batteries and hydrogen production via (photo)electrocatalytic water splitting. For the synthesis of multi-metal oxides, the preferred choice of solution-based methods is often motivated by their versatility, scalability, and high degree of composition and morphology control. Besides the highly controllable material properties that result from solution-based methods, the specific precursor chemistry can and should also address sustainability, atom economy and energy efficiency. An additional challenge in mentioned applications is related to the rapidly growing demand for more efficient storage of renewable energy, combined with the fast-growing electrification of transport. This surge is leading to a tremendous increase in the need for electrode materials, many of which rely on elements with vulnerable supply chains. Consequently, there is a pressing need to find alternative materials.<br/><br/>In this lecture, we will explore the challenges and opportunities in this field, drawing on our insights in the water-based solution-gel synthesis, e.g., of copper-based oxide electrodes for photoelectrochemical water splitting. Besides, special attention will be given to some innovative chemistries designed to facilitate low temperature and hence energy-efficient synthesis of complex multi-metal oxides. We will discuss approaches such as chemical design of precursor complexes for an adjusted gel-network or UV-assisted precursor decomposition in sol(ution)-gel synthesis, and auto-combustion synthesis.<br/>Addressing the urgent need to find alternatives to cobalt in the currently dominating LiNi_xMn_yCo_zO₂ (NMC) cathodes of lithium-ion batteries, it is key to develop innovative materials with lower cobalt content or even entirely cobalt-free alternatives. Several options exist, among which spinel or layered oxide structures. Unfortunately, their commercialization faces hurdles due to chemical or structural degradation during electrochemical operation. We will highlight the important influence of the synthesis methods on the properties of such materials and provide some of our recent solution-based approaches for element doping or surface engineering showing promise in stabilizing the structure and enhancing their performance.<br/>As securing a stable and affordable supply of lithium becomes increasingly challenging as well, we will finally discuss our exploration of above discussed solution-based methodologies for the development and improvement of electrode materials for sodium-ion batteries.<br/><br/>This work was supported by FWO-Vlaanderen (Research Foundation–Flanders) and by the HORIZON 2020 project COBRA (H2020-EU.3.4.−875568).<br/><br/>Selected References:<br/>D. De Sloovere, S. K. Mylavarapu, J. D’Haen, T. Thersleff, A. Jaworski, J. Grins, G. Svensson[MVB5] , R. Stoyanova, L. O. Jøsang, K. R. Prakasha, M. Merlo, E. Martínez, M. N. Pascual, J. Jacas Biendicho, M. K. Van Bael & A. Hardy, SMALL, 2400876 (2024).<br/>B. Joos, K. Elen, J. van den Ham, N. Meulendijks, P. Buskens, A. Paulus, K. Wouters, J. Manca, J. D’Haen, S. Shukla, B. Vermang, M.K. Van Bael & A. Hardy, ADVANCED SUSTAINABLE SYSTEMS, 7, 2300083 (2023)<br/>W. Marchal, D. Desloovere, M. Daenen, M.K. Van Bael & A.Hardy. CHEMISTRY A EUROPEAN JOURNAL, 26, 42, 9070 (2019).<br/>D. De Sloovere, M. Safari, K. Elen, J. D’Haen, O.A. Drozhizhin, A.M. Abakumov, M. Simenas, J. Banys, J. bekaert, B. Partoens, M. K. Van Bael & A. Hardy. CHEMISTRY OF MATERIALS, 30, 23, 8521 (2018)