Ni-rich layered oxides have been intensively considered as promising cathode materials for next-generation Li-ion batteries. Nevertheless, the performance degradation caused by intergranular cracks and electrode/electrolyte interface parasitic reactions restricts their further application. Compared with secondary particles, single-crystal (SC) materials have better mechanical integrity and cycling stability. However, the preparation of ultrahigh-nickel layered SC cathode still remains a serious challenge. Herein, a novel LiOH-LiNO₃-H₃BO₃ molten-salt method is proposed to synthesize SC LiNi_0.92Co_0.06Mn_0.02O₂ with considerable crystallinity and uniformity. The critical impacts of calcination temperature and boric acid on the microstructure and electrochemical property of Ni-rich layered oxides are systematically investigated. The results show that the crystal growth is promoted and the stability of crystal structure is improved by this synthesis method. In particular, the optimal electrode demonstrates a superior initial discharge capacity of 214.8 mAh g^–1 with a high capacity retention of 86.3% over 300 cycles as tested by pouch-type full cells at 45 ºC. This work not only prepares an ultrahigh-nickel layered CS cathode with superior electrochemical performances, but also provides a feasible method for the synthesis of other CS layered cathode materials.

中文翻译：

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一种熔盐法合成具有优异电化学性能的超高镍单晶LiNi0.92Co0.06Mn0.02O2作为锂离子电池正极材料

富镍层状氧化物已被广泛认为是下一代锂离子电池的有前途的正极材料。然而，由晶间裂纹和电极/电解质界面寄生反应引起的性能下降限制了它们的进一步应用。与二次粒子相比，单晶（SC）材料具有更好的机械完整性和循环稳定性。然而，制备超高镍层状SC正极仍然是一个严峻的挑战。本文提出了一种新型LiOH-LiNO ₃ -H ₃ BO ₃熔盐法合成SC LiNi _0.92 Co _0.06 Mn _0.02 O ₂具有相当的结晶度和均匀度。系统研究了煅烧温度和硼酸对富镍层状氧化物微观结构和电化学性能的关键影响。结果表明，该合成方法促进了晶体生长，提高了晶体结构的稳定性。特别是，在 45 ºC 的袋式全电池测试中，最佳电极表现出 214.8 mAh g ^{–1的优异初始放电容量和 300 次循环后 86.3% 的高容量保持率。}该工作不仅制备了具有优异电化学性能的超高镍层状CS正极，而且为其他CS层状正极材料的合成提供了可行的方法。