Journal of Power Sources (IF：6.945)
Volume 406，October 2018，Pages 110-117
Enhanced cycle stability of Na 0.9 Ni 0.45 Mn 0.55 O 2 through tailoring O3/P2 hybrid structures for sodium-ion batteries
Jie Chen,Lingjun Li∗, Ling Wu, Qi Yao, Huiping Yang, Zengsheng Liu, Lingfeng Xia,Zhaoyong Chen,Junfei Duan, Shengkui Zhong
A critical challenge for the practical use of the layered O3-type binary nickel manganese oxides for sodium-ion batteries is the poor structural stability during extended cycling. The approaches of constructing O3/P2 hybrid composites can partially improve the cycling stability, but general approaches sacrifice the advantages of high capacity and low cost of the O3-type cathodes due to excessive sodium deficiency and lithium substitution. Here,we rationally design a serial of novel O3-majority hybrid Na 0.9-x Ni 0.45 Mn 0.55 O 2 (x= 0.02, 0.04 and 0.08) cathodes, which exhibit high capacities while maintaining exceptional long-term stability. Particularly, the optimized O3/P2 Na 0.88 Ni 0.45 Mn 0.55 O 2 composite delivers 106.7mA h·g −1 with 71.1% capacity retention after250 cycles at 1C (1C= 150mA g −1 ), the cyclability is 32% higher than that of the O3eNa 0.9 Ni 0.45 Mn 0.55 O 2cathode; and it also delivers a initial discharge capacity of 75.9 mA h·g −1 , maintaining 72.4% capacity retention after 1000 cycles at 10 C. More importantly, the post-cycling analyses demonstrate O3/P2 hybrid phases suc-cessfully suppress the structural degradation of Na 0.9 Ni 0.45 Mn 0.55 O 2 during battery operation. This study pro-vides new perspectives in designing high performance cathodes for sodium-ion batteries.