TiNb2O7 nanoparticles modified by selenium doping and carbon coating for enhanced electrochemical performance as anodes in lithium-ion batteries

TiNb 2 O 7 (TNO) is regarded as a highly promising anode material for lithium-ion batteries, attributed to its high theoretical capacity, relatively high operating voltage, and excellent structural stability. However, its intrinsic poor electronic and ionic conductivities significantly hinder its practical application in lithium-ion batteries. In this study, Se-doped TNO@C nanoparticles were first synthesized through a facile solvothermal method, followed by carbon coating using glucose as the carbon source to form Se-TNO@C nanoparticles. Systematic material characterization and electrochemical performance tests were conducted on the as-prepared Se-TNO@C nanoparticles. Electrochemical tests revealed that the modified TNO anode exhibits a reversible capacity of 301.49 mA h/g after 100 cycles at 0.2C, alongside an impressive rate capability retention of 87.9 %. Furthermore, Se-TNO@C exhibits good cycling stability at high current densities. Specifically, after 300 cycles, it delivers reversible capacities of 249.31 mA h/g at 2C. This study provides a novel strategy to enhance the electrochemical performance of anode materials for lithium-ion batteries. • TiNb 2 O 7 was modified via a dual modification strategy of Se doping and carbon coating. • TiNb 2 O 7 has successfully achieved markedly higher specific capacity and superior cycling stability. • The doping-induced lattice expansion and uniform carbon coating synergistically optimize the material's structure.