Mo-based compounds coating to stabilize Mn-based layered oxide cathode material towards high-performance Na-ion batteries with ultrahigh cycling stability

Abstract

Layered oxide cathode materials have good structural stability and high capacity, making them ideal cathode materials of Na-ion batteries (SIBs). Nonetheless, the irreversible phase transitions and metal dissolution often result in poor cycling stability. Here, a simple strategy was developed to Na2MoO4 and MoO3 coated Na0.67Fe0.15Cu0.1Mn0.65Ni0.1O2 (NFCMN-M) as cathode material of SIBs with ultrahigh cycling stability caused by the enhanced kinetic. The formed Na2MoO4 layer on the surface of Na0.67Fe0.15Cu0.1Mn0.65Ni0.1O2 (NFCMN) particles supplies a good conductive connection, and inhibits side effects between cathode material and electrolyte. Thanks to the unique component, the as-prepared NFCMN-M shows a good rate performance with a reversible discharge capacity of 132.4, 112.6, 102.3, 87.1 and 79.3 mAh g−1 at 0.1, 0.5, 1, 3 and 5C, respectively. The NFCMN-M also delivers an initial capacity of 73.7 mAh g−1 at 10C and an ultrahigh cycling stability with a capacity retention rate of about 80 % after 1000 cycles. The result confirms that the Na2MoO4 modification is a direct and effective strategy to improve the capacity and enhance cycling stability of NFCMN at high charge-discharge rates.