Synergistic effects of charge redistribution and morphology regulation in Mo-doped TiNb2O7 anodes for solid-state battery applications

TiNb 2 O 7 (TNO) is a promising anode for lithium-ion batteries owing to its high theoretical capacity, minimal volume expansion, and effective suppression of lithium dendrite formation. Nonetheless, the low electrical conductivity of TNO presents a barrier to practical application. Thus, a Mo 6+ doping strategy was utilized to address the conductivity issue, and TNO- x Mo ( x  = 0, 0.05, 0.10, 0.15, 0.20) anodes were prepared by a solid-state method. The incorporation of Mo 6+ ions result in a charge redistribution, which can elevate electronic conductivity and accelerate ion diffusion. What’s more, by precisely controlling the Mo 6+ ion concentration can regulate the morphologies of the TNO, enabling it to expose more fast-ion conducting (020) facets. The synergistic effect of the above two factors significantly enhances the conductivity and electrochemical properties of the TNO anode. As a result, the optimal TNO-0.05Mo with 2D lamellar structure exhibits a high discharge capacity of 347.6 mAh g −1 at 0.1C, superior rate performance, and an excellent cycle lifespan, with retention of 78% after 1500 cycles at 1.5C/1.5C. Meanwhile, the solid-state battery with TNO-0.05Mo as anode also displays improved rate and cycle performance than the liquid-state battery, indicating the great application potential for the next-generation energy storage devices.