CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, and Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P. R. China.
University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China.
Small Methods. 2023 Jul;7(7):e2300280. doi: 10.1002/smtd.202300280. Epub 2023 Apr 22.
Ni-rich layered cathodes with ultrahigh nickel content (≥90%), for example LiNi Co O (NC0.9), are promising for next-generation high-energy Li-ion batteries (LIBs), but face stability issues related to structural degradation and side reactions during the electrochemical process. Here, surface modulation is demonstrated by integrating a Li -conductive nanocoating and gradient lattice doping to stabilize the active cathode efficiently for extended cycles. Briefly, a wet-chemistry process is developed to deposit uniform ZrO(OH) nanoshells around Ni Co (OH) (NC0.9-OH) hydroxide precursors, followed by high temperature lithiation to create reinforced products featuring Zr doping in the crust lattice decorated with Li ZrO nanoparticles on the surface. It is identified that the Zr infiltration reconstructed the surface lattice into favorable characters such as Li deficiency and Ni reduction, which are effective to combat side reactions and suppress phase degradation and crack formation. This surface control is able to achieve an optimized balance between surface stabilization and charge transfer, resulting in an extraordinary capacity retention of 96.6% after 100 cycles at 1 C and an excellent rate capability of 148.8 mA h g at 10 C. This study highlights the critical importance of integrated surface modulation for high stability of cathode materials in next-generation LIBs.
富镍层状正极材料（镍含量≥90%，例如 LiNi Co O）具有很大的应用潜力，可用于下一代高能量密度锂离子电池（LIB），但其在电化学过程中面临结构降解和副反应等稳定性问题。本研究通过整合具有锂离子导电性的纳米涂层和梯度晶格掺杂对正极材料进行表面修饰，以提高正极材料的稳定性并延长循环寿命。具体来说，通过湿化学法在 Ni Co（OH）（NC0.9-OH）前驱体表面均匀包覆 ZrO(OH)纳米壳，然后在高温下进行锂化处理，在壳层晶格中引入 Zr 掺杂，同时在表面修饰具有锂离子导电性的 Li ZrO 纳米颗粒。研究结果表明，Zr 的渗透重构了表面晶格，形成了有利的 Li 缺乏和 Ni 还原特征，从而有效抑制了副反应、相降解和裂纹的形成。这种表面调控能够实现表面稳定化和电荷转移之间的优化平衡，在 1 C 下循环 100 次后，容量保持率高达 96.6%，在 10 C 下的倍率性能高达 148.8 mA h g。本研究强调了综合表面修饰对下一代 LIB 中正极材料高稳定性的关键作用。
