Single-crystal nickel-rich layered-oxide battery cathode materials: synthesis, electrochemistry, and intra-granular fracture
2020; Elsevier BV; Volume: 27; Linguagem: Inglês
10.1016/j.ensm.2020.01.027
ISSN2405-8297
AutoresGuannan Qian, Youtian Zhang, Linsen Li, Ruixin Zhang, Junmeng Xu, Zhenjie Cheng, Sijie Xie, Han Wang, Qunli Rao, Yu‐Shi He, Yanbin Shen, Liwei Chen, Ming Tang, Zi‐Feng Ma,
Tópico(s)Advanced Battery Technologies Research
ResumoElectro-mechanical degradation is commonly observed in various battery electrode materials, which are often prepared as polycrystalline particles consisting of nanoscale primary grains. The anisotropic volume change during lithium extraction/insertion makes these materials intrinsically vulnerable to grain-boundary (inter-granular) fracture that leads to rapid impedance growth and capacity decay. Here, guided by fracture mechanics analysis, we synthesize microsized single-crystal Ni-rich layered-oxide (NMC) cathode materials via an industrially-applicable molten-salt approach. Using single-crystal LiNi0.6Mn0.2Co0.2O2 as a model material, we show that the cycle performance of the Ni-rich NMC can be significantly improved by eliminating the internal grain boundaries and inter-granular fracture. The single-crystal LiNi0.6Mn0.2Co0.2O2 cathodes show high specific capacity (183 mAh g−1 at 0.1 C rate, 4.3–2.8 V) and excellent capacity retention (94% after 300 cycles at 1C/1C cycling). Further, it is confirmed for the first time that the single-crystal LiNi0.6Mn0.2Co0.2O2 particles are stable against intra-granular fracture as well under normal operating conditions but do crack if severely overcharged. Electrochemical-shock resistant single-crystal NMC reveals an alternative path towards developing better battery cathode materials, beyond the traditional one built upon polycrystalline NMC.
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