制备异质结构以提高富锂正极的结构稳定性
Fabricating Heterostructures for Boosting the Structure Stability of Li-Rich Cathodes.
作者信息
Li Yao, Zhao Qing, Zhang Mengke, Qiu Lang, Zheng Zhuo, Liu Yang, Sun Yan, Zhong Benhe, Song Yang, Guo Xiaodong
机构信息
College of Chemical Engineering, Sichuan University, Chengdu 610065, Sichuan, China.
The State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, Sichuan, China.
出版信息
ACS Omega. 2023 Feb 13;8(7):6720-6728. doi: 10.1021/acsomega.2c07313. eCollection 2023 Feb 21.
Li-rich Mn-based oxides are regarded as the most promising new-generation cathode materials, but their practical application is greatly hindered by structure collapse and capacity degradation. Herein, a rock salt phase is epitaxially constructed on the surface of Li-rich Mn-based cathodes through Mo doping to improve their structural stability. The heterogeneous structure composed of a rock salt phase and layered phase is induced by Mo enriched on the particle surface, and the strong Mo-O bonding can enhance the TM-O covalence. Therefore, it can stabilize lattice oxygen and inhibit the side reaction of the interface and structural phase transition. The discharge capacity of 2% Mo-doped samples (Mo 2%) displays 279.67 mA h g at 0.1 C (vs 254.39 mA h g (pristine)), and the discharge capacity retention rate of Mo 2% is 79.4% after 300 cycles at 5 C (vs 47.6% (pristine)).
富锂锰基氧化物被认为是最有前途的新一代正极材料，但其实际应用受到结构坍塌和容量衰减的极大阻碍。在此，通过钼掺杂在富锂锰基正极表面外延构建岩盐相，以提高其结构稳定性。颗粒表面富集的钼诱导出由岩盐相和层状相组成的异质结构，且强的Mo-O键能增强过渡金属-氧（TM-O）共价性。因此，它能稳定晶格氧并抑制界面副反应和结构相变。2%钼掺杂样品（Mo 2%）在0.1 C下的放电容量为279.67 mA h/g（原始样品为254.39 mA h/g），Mo 2%在5 C下循环300次后的放电容量保持率为79.4%（原始样品为47.6%）。
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