Polyaniline cathode for dual-ion rechargeable Mg batteries

Rechargeable Mg batteries (RMBs) are advantageous for large-scale applications with the abundant reserves and high safety, but traditional Mg-storage cathodes suffer from low capacities and sluggish Mg2+ diffusion kinetics. Herein, new RMBs are constructed with p-doping cathode of polyaniline (PANI), which overcomes the shortcomings of Mg-storage. The PANI cathode provides a capacity of 125.0 mAh g−1 at 50 mA g−1, a good rate performance with 72.4 mAh g−1 at 2.0 A g−1 and a stable cyclability for 200 cycles. Further ex-situ investigation demonstrates the p-doping mechanism for the PANI cathode. This study highlights a new strategy to develop high-performance RMBs.