Increasing the Energy Density of Disordered Rock Salt Anodes for Fast-Charging Lithium-Ion Batteries

Transition-metal oxides (TMOs) are promising anode materials for safe and fast-charging batteries, but their high operating potentials limit energy density. Here, we develop a strategy to suppress the operating potential of the disordered rock salt (DRS) Li3V2O5 (LVO) anode by {$\sim$}10\% to 0.54 V via Mg doping. Density functional theory (DFT) calculations attribute this voltage reduction to increased site energy of Li ions because of Mg doping, with minimal impact on Li migration barriers. Mgdoped LVO retains over 95\% of its capacity over 1000 cycles at a rate of 5 C. Full cells with a LiNi0.8Co0.1Mn0.1O2 cathode demonstrate the expected increase in cell voltage and energy density while retaining 91\% of their capacity over 250 cycles at 5 C. Our findings show that Mg doping provides a promising pathway for designing fast-charging, long-cycle-life anode materials with enhanced energy density.