Combining Quinone‐Based Cathode with an Efficient Borate Electrolyte for High‐Performance Magnesium Batteries

Rechargeable magnesium batteries are gaining attention as promising candidates for large-scale energy storage applications because of their potentially high energy, safety and sustainability. However, the development Mg is impeded by lack efficient cathode materials compatible electrode-electrolyte combinations. Herein, we demonstrate a new poly(1,4-anthraquinone)/Ketjenblack composite (14PAQ@KB) in combination with non-corrosive tetrakis(hexafluoroisopropyloxy) borate Mg[B(hfip)4]2 (hfip=OC(H)(CF3)2) electrolyte towards high-energy long-lifespan batteries. This exhibits prominent electrochemical performance including maximum discharge capacity 242 mA h g−1 (approximately 93 % theoretical capacity), superior cycling stability (81 after 1000 cycles), excellent rate capability (120 at 5 C).