LiCrTiO4 Nanowires as High-Performance Cathodes for Magnesium–Lithium Hybrid Batteries

Abstract

Magnesium–lithium hybrid batteries attract considerable attention due to combined advantages of metallic magnesium anode (free dendrite) and Li-driven reaction cathode (fast ion diffusion rate). In this work, nanowired LiCrTiO4 with moderate redox potential is chosen as a potential cathode material for magnesium–lithium hybrid batteries. LiCrTiO4 nanowires are made up of small dispersed nanoparticles. In such a structure, the diffusion/migration barrier of Li+ insertion is reduced and the infiltration of electrolyte is enhanced, leading to faster ion diffusion rates and smaller potential polarization. The Mg2+/Li+ hybrid battery exhibits a high reversible capacity (128.7 mA h g–1 after 100 cycles at 50 mA g–1) and excellent rate performance (even at a high current density of 500 mA g–1, a specific capacity of 110.1 mA h g–1 can be still achieved, corresponding to 67.8% of that at 30 mA g–1). Notably, the ion storage mechanism of LiCrTiO4 nanowires in Mg2+/Li+ hybrid battery is systematically investigated by ex situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy. This research demonstrates that the nanowired LiCrTiO4 cathode is a high-performance candidate for magnesium–lithium hybrid batteries.