Large-Scale Synthesis of NaNi_1/3Fe_1/3Mn_1/3O₂as High Performance Cathode Materials for Sodium Ion Batteries

Layered transition metal oxides Na x Ni 1/3 Fe 1/3 Mn 1/3 O 2 are promising cathode materials for sodium ion batteries. Here we report the large scale synthesis of NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NaNFM) by using hydroxide co-precipitation combined with solid-state reaction method. The obtained NaNFM showed good electrochemical performance with 1C rate (130 mA g −1 ) capacities of 125 mAh g −1 (55°C), 122 mAh g −1 (25°C), 95 mAh g −1 (−10°C), and 72 mAh g −1 (−20°C), respectively. 1 Ah soft-packed batteries using the prepared NaNFM as cathode and hard carbon as anode were prepared and investigated. Electrochemical tests showed that the as prepared 1 Ah soft-packed batteries exhibited excellent cycling performance with capacity retention over 73% after 500 cycles at 1C rate. The ex situ XRD experiments revealed that the charge/discharge process of Na x Ni 1/3 Fe 1/3 Mn 1/3 O 2 cathode showed excellent reversibility and the layered crystallographic structure of the NaNFM electrode remained stable after 500 cycles. This work demonstrates the NaNi 1/3 Fe 1/3 Mn 1/3 O 2 is a promising cathode material for practical application in sodium ion batteries.