Facile synthesis of nickel-doped Co9S8 hollow nanoparticles with large surface-controlled pseudocapacitive and fast sodium storage

Transition metal sulfides are considered to be promising candidates as anodes for sodium ion batteries (SIBs). However, their further applications are limited by poor electrical conductivity and sluggish electrochemical kinetics. We report, for the first time, nickel-doped Co9S8 hollow nanoparticles as SIB anodes with enhanced electrical conductivity and a large pseudocapacitive effect, leading to fast kinetics. This compound exhibits excellent sodium storage performance, including a high capacity of 556.7 mA h g(-1), a high rate capability of 2000 mA g(-1) and an excellent stability up to 200 cycles. The results demonstrate that nickel-doped Co9S8 hollow nanoparticles are a promising anode material for SIBs.