A facile gaseous sulfur treatment strategy for Li-rich and Ni-rich cathode materials with high cycling and rate performance

Sun, ZH (Sun, Zhenhe)^{[ 1,2 ]} ; Xu, LQ (Xu, Lingqun)^{[ 1,2 ]} ; Dong, CQ (Dong, Caiqiao)^{[ 1,2 ]} ; Zhang, HT (Zhang, Hongtao)^{[ 1,2,3 ]} ; Zhang, MT (Zhang, Mingtao)^{[ 1,2 ]} ; Ma, YF (Ma, Yanfeng)^{[ 1,2,3 ]} ; Liu, YY (Liu, Yiyang)^{[ 4 ]} ; Li, ZJ (Li, Zhongjun)^{[ 4 ]} ; Zhou, Y (Zhou, Ying)^{[ 1,2 ]} ; Han, Y (Han, Yu)^{[ 1,2 ]} ; Chen, YS (Chen, Yongsheng)^{[ 1,2,3 ]}

NANO ENERGY, 2019, 63, 文献号: UNSP 103887

DOI: 10.1016/j.nanoen.2019.103887

摘要

Lithium-rich and Ni-rich cathode materials have been considered as the attractive candidate for their high capacitive performance, but usually exhibit poor rate performance and limited cycle life. Herein, a facile gaseous sulfur treatment was developed to uniformly create oxygen vacancies and replace oxygen with sulfur atoms at the surface region of lithium-rich and Ni-rich cathode materials. Such a treatment, when applied to typical Li- or Ni- rich materials such as Li1.2Ni0.13Co0.13Mn0.54O2 (LNCMO), Li1.2Ni0.2Mn0.6O2 (LNMO) and LiNi0.8Co0.1Mn0.1O2 (NCM811), could enhance significantly all their cycle and rate performance. For example, LNCMO@S obtained from LNCMO, could exhibit a capacity retention of 81.10% after 600 cycles at 0.5 C (compared with 65.78% of LNCMO after 200 cycles), together with an excellent rate performance of 174.8 mA h g(-1) at 10 C (compared with 133.3 mA h g(-1) of LNCMO), which is among the best performance for all Li-rich cathode materials. The revealed mechanism, where the partial replacement of O by S at the lattice surface significantly reduces oxygen partial pressure and also enhances the Li ion conductivity, might shed light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for Li-ion batteries with high energy and power density.