Liu Huiqiao, He Yanan, Gao Zihui, Zhang Gaoyang, Cao Kangzhe, Jing Qiang-Shan
College of Chemistry and Chemical Engineering, Henan Province Key Laboratory of Utilization of Non-Metallic Mineral in the South of Henan, Xinyang Normal University, Xinyang 464000, China.
College of Chemistry and Chemical Engineering, Henan Province Key Laboratory of Utilization of Non-Metallic Mineral in the South of Henan, Xinyang Normal University, Xinyang 464000, China.
J Colloid Interface Sci. 2022 Jan 15;606(Pt 2):1101-1110. doi: 10.1016/j.jcis.2021.08.100. Epub 2021 Aug 18.
Conversion anode materials such as MnO draw much attention due to their considerable theoretical capacity for lithium-ion batteries (LIBs). However, poor conductivity, slow solid-state Li-ion diffusion, and huge volume expansion of the active materials during charge/discharge lead to unsatisfied electrochemical performance. Despite several strategies like nanocrystallization, fabricating hierarchical nanostructures, and introducing a matrix are valid to address these crucial issues, the achieved electrochemical performance still needs to be further enhanced. What is worse, the matrix with less or no Li-ion storage activity may lower the achieved capacity of the electrodes. Herein, ultra-thin CuMnO nanosheets with the thickness of 5-8 nm were evaluated for LIBs. The ultra-thin sheet-like nanostructure offers sufficient contact areas with electrolyte and shortens the Li-ion diffusion distance. Moreover, the in-situ generated Mn and Cu along with their oxides could play the role of matrix and conductive agent in turn at different stages, relieving the stress brought by volume expansion. Therefore, the as-prepared ultra-thin CuMnO nanosheets electrode displays a remarkable reversible capacity, long cycling stability, and outstanding rate capability (a reversible capacity of 1160.5 mAh g at 0.1A g was retained after 100 cycles with a capacity retention of 95.1 %, and 717.8 mAh g at 2.0 A g after 400 cycles).
诸如MnO之类的转化型阳极材料因其对锂离子电池（LIBs）具有可观的理论容量而备受关注。然而，导电性差、固态锂离子扩散缓慢以及活性材料在充放电过程中巨大的体积膨胀导致电化学性能不尽人意。尽管诸如纳米晶化、构建分级纳米结构以及引入基体等几种策略对于解决这些关键问题是有效的，但所实现的电化学性能仍需进一步提高。更糟糕的是，具有较少或没有锂离子存储活性的基体可能会降低电极所实现的容量。在此，对厚度为5 - 8纳米的超薄CuMnO纳米片进行了锂离子电池评估。这种超薄的片状纳米结构提供了与电解质足够的接触面积，并缩短了锂离子扩散距离。此外，原位生成的Mn和Cu及其氧化物在不同阶段依次可以起到基体和导电剂的作用，缓解体积膨胀带来的应力。因此，所制备的超薄CuMnO纳米片电极展现出显著的可逆容量、长循环稳定性和出色的倍率性能（在0.1A g下100次循环后，可逆容量为1160.5 mAh g，容量保持率为95.1%；在2.0 A g下400次循环后，可逆容量为717.8 mAh g）。
