Hu Qian, Xu Laiqiang, Liu Gonggang, Hu Jinbo, Ji Xiaobo, Wu Yiqiang
College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
College of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, China.
ACS Nano. 2024 Aug 13;18(32):21491-21503. doi: 10.1021/acsnano.4c06281. Epub 2024 Jul 31.
Hard carbon (HC) is a promising anode material for sodium-ion batteries. However, the intrinsic relationship between the closed pores/surface groups and sodium storage performance has been unclear, leading to difficulties in targeted regulation. In this study, renewable tannin extracts were used as raw materials to prepare HC anodes with abundant tunable closed pores and carbonyl groups through a pyrolytic modulation strategy. Combining ex situ characterizations reveals that closed pores and carbonyl groups are regulated by the pyrolytic process. Further, it is demonstrated that the plateau region is mainly contributed by the closed pores; highly stable fluorine-rich solid electrolyte interphase compositions are produced through carbonyl-induced interfacial catalysis. The optimized HC anode displays good cycling stability, exhibiting a high reversible capacity (360.96 mAh g) at 30 mA g and capacity retention of up to 94% after 500 cycles at 1 A g. Moreover, the full battery assembled with NaV(PO)/C demonstrates a stable cycling performance. These findings provide a fresh knowledge of the structural design of high-performance HC anode materials and the mechanism of sodium storage in HC.
硬碳（HC）是一种很有前景的钠离子电池负极材料。然而，封闭孔隙/表面基团与储钠性能之间的内在关系尚不清楚，导致难以进行有针对性的调控。在本研究中，以可再生单宁提取物为原料，通过热解调制策略制备了具有大量可调控封闭孔隙和羰基的HC负极。结合非原位表征表明，封闭孔隙和羰基受热解过程调控。此外，研究表明，平台区主要由封闭孔隙贡献；通过羰基诱导的界面催化产生了高度稳定的富氟固体电解质界面组成。优化后的HC负极表现出良好的循环稳定性，在30 mA g下具有高可逆容量（360.96 mAh g），在1 A g下循环500次后容量保持率高达94%。此外，用NaV(PO)/C组装的全电池表现出稳定的循环性能。这些发现为高性能HC负极材料的结构设计和HC中储钠机制提供了新的认识。
