ORALS

Lithium-ion batteries are widely used as energy storage devices for electric vehicles and large-scale energy storage systems. Nevertheless, there are growing concerns about the limited availability of lithium resources, which could result in depletion and increased prices in the future. To tackle this issue, scientists have been extensively investigating alternative secondary battery systems that can replace commercial lithium-ion batteries. Sodium-ion batteries have attracted considerable interest among these alternatives due to the abundance of sodium resources and its economic feasibility compared to lithium. [1] Although hard carbon has been recognized as a reversible anode material that enables sodium-ion insertion and extraction, the demand for high-capacity anode materials is imperative to achieve the desired energy density in sodium-ion batteries. Conversion- and alloy-based materials are considered highly promising alternatives due to their substantial theoretical capacity for sodium storage. [2,3] However, these materials encounter challenges such as notable volume changes of the active components, slow reaction kinetics, and instability at the electrode interfaces during the sodiation and desodiation processes. Overcoming these obstacles is essential to effectively implement these materials in high-performance sodium-ion batteries. [4] In order to address these challenges, we devised a novel approach in this study, which involved the design of heterostructured anodes with a unique architecture. This was achieved by combining conversion- or alloy-based active materials with a porous silicon oxycarbide (SiOC) nanocoating layer, which is known for its exceptional surface capacitive reactivity and mechanical strength. We synthesized heterostructured composite anodes (MoS2@SiOC and Sn@SiOC) by controlling the dispersion of precursors in silicon oil and subsequent heat treatment. To investigate the properties of these composites, we conducted extensive physicochemical and electrochemical characterization, as well as post-mortem analysis. Our focus was particularly on understanding how the heterostructure influenced the battery performance of these composites. By adopting this heterostructure approach, we anticipate that new possibilities will arise for the development of innovative and high-performance anode materials for sodium-ion batteries.

References:
[1] C. Vaalma, D. Buchholz, M. Weil, S. Passerini, Nat. Rev. Mater. 3 (2018) 1-11. [2] P. Tao, J. He, T. Shen, Y. Hao, J. Yan, Z. Huang, X. Xu, M. Li, Y. Chen, Adv. Mater. Interfaces 6 (2019) 1900460. [3] H.T. Tan, D. Chen, X.H. Rui, Y. Yu, Adv. Funct. Mater. 29 (2019) 1808745. [4] S.Z. Liang, Y.J. Cheng, J. Zhu, Y.G. Xia, P. Muller-Buschbaum, Small Methods 4 (2020) 2000218.