State Key Laboratory of Marine Resources Utilization in South China Sea, Key Laboratory of Research on Utilization of Si-Zr-Ti Resources of Hainan Province, School of Materials Science and Engineering, Hainan University, Haikou 570228, China.
Guangdong Key Laboratory for Hydrogen Energy Technologies; School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China.
ACS Appl Mater Interfaces. 2023 May 31;15(21):25567-25574. doi: 10.1021/acsami.3c03173. Epub 2023 May 18.
As a graphite-like material, the LiBC can deliver a high capacity up to 500 mA h g in Li-ion batteries, which is dependent on the carbon precursor, the high-temperature treatment, and the lithium insufficiency. However, the underlying mechanism is still not clear for the electrochemical reactions of LiBC. In this work, the pristine LiBC was reacted with aqueous solutions of different alkalinity, which was delithiated chemically and retained the layered structure. According to the XPS and NMR results, the B-B bond might be produced through the aqueous reaction or the initial charge process, which can be oxidized (charged) and reduced (discharged) in the electrochemical measurements. In the Li-ion battery, the reversible capacity of LiBC increases evidently with the alkalinity of aqueous solution and significantly rises to a similar value of ca. 285 mA h g under 200 cycles. Therefore, the specific capacity of LiBC should be contributed by the active sites of B-B bonds, which can be significantly increased through the reaction with the hydroxyl ions, and this strategy might be adopted to activate more graphite-like materials.
作为一种类似石墨的材料，LiBC 在锂离子电池中可以提供高达 500 mA h g 的高容量，这取决于碳前体、高温处理和锂不足。然而，LiBC 的电化学反应的潜在机制尚不清楚。在这项工作中，原始的 LiBC 与不同碱性的水溶液反应，通过化学脱锂并保留层状结构。根据 XPS 和 NMR 结果，B-B 键可能是通过水反应或初始充电过程产生的，在电化学测量中可以被氧化（充电）和还原（放电）。在锂离子电池中，LiBC 的可逆容量随着水溶液的碱性明显增加，在 200 次循环后显著上升至约 285 mA h g。因此，LiBC 的比容量应该归因于 B-B 键的活性位点，通过与羟基离子的反应可以显著增加，这种策略可能被用来激活更多类似石墨的材料。
