Insights into the Storage Mechanism of Layered VS2 Cathode in Alkali Metal‐Ion Batteries. Issue 22 (24th April 2020) - Zhang, Xiao
Abstract: VS2 is one of the attractive layered cathodes for alkali metal‐ion batteries. However, the understanding of the detailed reaction processes and energy storage mechanism is still inadequate. Herein, the Li + /Na + /K + insertion/extraction mechanisms of VS2 cathode are elucidated on the basis of experimental analyses and theoretical simulations. It is found that the insertion/extraction behavior of Li + is partially irreversible, while the insertion/extraction behavior of Na + /K + is completely reversible. The detailed intermediates and final products (Li0.33 VS2, LiVS2, Na0.5 VS2, NaVS2, K0.6 VS2, K z VS2, z > 0.6) during the discharging/charging processes are identified, indicating that VS2 undergoes different phase transitions and solid–solution reactions in different battery systems, which have a great influence on the battery performance. Moreover, the diffusion of Na + in VS2 cathode is demonstrated to be much slower than that of Li + and K + . Such mechanistic research provides a reference for in‐depth understanding of energy storage in layered transition metal sulfides/selenides. Abstract : The intermediates and final products produced at the VS2 cathode during the discharging/charging processes in alkali metal‐ion batteries are identified. VS2 enables partially irreversible Li + storage and wholly reversible storage of Na + /K + . A more complex phase transition process and the highest energy barrier for the diffusion of Na + in sodium‐ion batteries than the other two systems are discovered.