Engineering a high-capacity and long-cycle-life magnesium/lithium hybrid-ion battery using a lamellar SnSe₂/SnSe/SnO₂ cathode

Since the safety and costs of current lithium-ion batteries are non-ideal, engineering a new energy-storage systems is needed. Magnesium/lithium hybrid-ion batteries (MLHBs) combining fast kinetics of Li ions and a dendrite-free Mg anode are promising. Here, we describe our development of an MLHB using lamellar SnSe₂/SnSe/SnO₂ as cathode material and an all-phenyl complex (APC)-based electrolyte. The multi-layered cathode material generated from a hierarchical precursor is conducive to diffusion of Li⁺ and Mg²⁺ ions, and buffers volumetric changes efficiently. After 2000 cycles at 1.0 A g⁻¹, the battery shows a specific capacity of 233 mA h g⁻¹ and a Coulombic efficiency of 100%. It also shows excellent rate performances. These findings suggest that the cathode design working with optimized electrolyte will find many applications for high-performance energy-storage systems.