Enhanced performance of Mo-doped TiNb2O7 anode material for lithium-ion batteries via KOH sub-molten salt synthesis

Abstract

TiNb2O7 (TNO) as an electrode material for lithium-ion batteries (LIBs) has relatively high safety and high theoretical capacity, making it an excellent alternative to the graphite anode. Nevertheless, its practical application is limited by its sluggish ionic and electronic conductivity. To address this challenge, Mo-doped TiNb2O7 (Mo-TNO) is synthesized via a KOH sub-molten salt method followed by calcining process. In this method, the low-cost raw materials are co-dissolved and then coprecipitated to achieve homogeneous mixing and particle refinement, further ensuring the uniformity of calcined products. The doping of Mo6+ facilitates cation mixing and charge compensation, leading to reduced charge transfer resistance and enhanced electronic conductivity. The reversible specific capacity of Mo-TNO after 300 cycles is maintained at 148 mA h g−1 with a high capacity-retention of 80 % at 5C. Even at 30C, it still exhibits a better capacity of 100.2 mA h g−1, much higher than the pristine TNO (58.9 mA h g−1). Furthermore, the full battery employing Mo-TNO as an anode and commercial LiNi0.6Co0.2Mn0.2O2 (NCM) as a cathode exhibits superior electrochemical performances with promising application prospect. These findings underscore the significant potential of Mo-TNO as a high-rate and long-life anode material for LIBs.