MXene-derived TiO2@MXene nanocomposite cathodes for dual-salt magnesium/lithium-ion batteries

Magnesium-ion batteries offer a safer, cheaper alternative to lithium-ion systems thanks to magnesium's abundance, higher charge density, and a metal anode that's far less prone to dendrite formation. However, their practical application is hindered by sluggish ion diffusion kinetics and strong electrostatic interactions of magnesium ions, which significantly reduce cathode performance. To address these challenges, this study introduces a hybrid Mg/Li-ion battery featuring a uniquely engineered nanocomposite cathode of two-dimensional Ti 3 C 2 T x MXene decorated with TiO 2 nanoparticles (MD-TiO 2 @MXene400) and a dual-salt electrolyte. The nanocomposite cathode material is obtained by partially oxidizing Ti 3 C 2 T x MXene at 400 °C. This optimized cathode material delivers a high specific capacity of ∼208 mAh g −1 at 20 mA g −1 (about twice that of pristine MXene) and maintains excellent cycling stability, with 159 mAh g −1 retained after 300 cycles at 100 mA g −1 . The superior performance arises from the synergistic combination of conductive MXene layers and electrochemically active TiO 2 nanoparticles, which together mitigate sluggish ion transport and enhance structural stability. These findings highlight MXene-derived TiO 2 composites as promising cathode materials for next-generation multivalent hybrid batteries.