Bismuth-doping boosting Na<sup>+</sup> diffusion kinetics of layered oxide cathode with radially oriented {010} active lattice facet for sodium-ion batteries
Yuxin Chang, Yu‐Jie Guo, Ya‐Xia Yin, Wei‐Huan He, Mengmeng Yan, Lirong Zheng, Jing Zhang, Qinghua Zhang, Dong Su, Xing Zhang, Jianfeng Mao, Guanjie Li, Shilin Zhang, Sailong Xu
Abstract
O3-type layered oxide cathodes (Na x TMO 2 ) for sodium-ion batteries (SIBs) have attracted significant attention as one of the most promising potential candidates for practical energy storage applications. The poor Na + diffusion kinetics is, however, one of the major obstacles to advancing large-scale practical application. Herein, we report bismuth-doped O3-NaNi 0.5 Mn 0.5 O 2 (NMB) microspheres consisting of unique primary nanoplatelets with the radially oriented {010} active lattice facets. The NMB combines the advantages of the oriented and exposed electrochemical active planes for direct paths of Na + diffusion, and the thick primary nanoplatelets for less surface parasitic reactions with the electrolyte. Consequently, the NMB cathode exhibits a long-term stability with an excellent capacity retention of 72.5% at 1 C after 300 cycles and an enhanced rate capability at a 0.1 C to 10 C rate (1 C = 240 mA g –1 ). Furthermore, the enhancement is elucidated by the small volume change, thin cathode-electrolyte-interphase (CEI) layer, and rapid Na + diffusion kinetics. In particular, the radial orientation-based Bi-doping strategy is demonstrated to be effective at boosting electrochemical performance in other layered oxides (such as Bi-doped NaNi 0.45 Mn 0.45 Ti 0.1 O 2 and NaNi 1/3 Fe 1/3 Mn 1/3 O 2 ). The results provide a promising strategy of utilizing the advantages of the oriented active facets of primary platelets and secondary particles to develop high-rate layered oxide cathodes for SIBs.