Insight into Mg-doping effects on Na3Ni2SbO6 cathode host for Na-ion batteries

•Mg-doped sodium nickel antimonites were prepared via solid-state synthesis.•Mg-doped Na3Ni2−xSbO6 shows enhanced electrochemical performance.•Mg-doped Na3Ni2−xSbO6 shows reduced volumetric change upon recharge.

Recently, a novel antimonite layered Na-ion cathode material, Na3Ni2SbO6, exhibited promising electrochemical performance. However, there has been no research whether this framework allows structural variations that could further enhance its electrochemical performance. Here we have tested Na3Ni2−xMgxSbO6 (x=0, 0.25, and 0.5) solid phases. Having slightly decreased specific capacities, Mg-doped Na3Ni2SbO6 shows enhanced rate performance due to better structural integrity and slightly lowered unit cell volume changes upon desodiation.