A high-performance magnesium/lithium hybrid-ion battery using a hollow multi-layered NiS/Co 3 S 4 /carbon cathode and an all-phenyl-complex-based electrolyte.

Magnesium-lithium hybrid batteries (MLHBs) using a dual-ion electrolyte and safe Mg anode have promising potential for high-performance energy storage. Here, we develop an MLHB constructed of a hollow multi-layered NiS/Co 3 S 4 /carbon cathode and an all-phenyl-complex/lithium chloride (APC-LiCl) electrolyte. The hollow multi-layered structure and carbon matrix accommodate volumetric expansion and facilitate electrolyte penetration. The APC-LiCl electrolyte displays a stable electrochemical window. The MLHB shows a high specific capacity of 398 mA h g -1 after 100 cycles at 0.2 A g -1 , and a stable capacity at 1.0 A g -1 after cycling 500 times. Moreover, stable rate performance and temperature tolerance are achievable. These findings would enable this design to be promising for developing other hybrid battery systems.