A Solid Electrolyte Based on Electrochemical Active Li₄Ti₅O₁₂ with PVDF for Solid State Lithium Metal Battery

In parallel with researches unveiling the nature and mechanism in solid state battery, numbers of investigations have been pursuing methods to stabilize their performance as well as to reduce the cost. Simple preparation and earth-abundant ingredients are preconditions for a solid state electrolyte to be suitable for scalable production. In this work, a commercial anode active material, spinel Li₄Ti₅O₁₂, is introduced for the first time, which has high ionic conductivity to sustain high rate charge/discharge with considerable high performance/cost ratio, into poly(vinylidene fluoride) to achieve a composite solid electrolyte. The membrane solid electrolyte containing 80 wt% of the Li₄Ti₅O₁₂ (LTO-8) shows outstanding ionic conductivity of 2.87 × 10⁻⁴ S cm⁻¹ at 35 °C and inhibits electronic conductive network. The self-sacrificed interface contributes to the stabilized performance of the composite. Li||LiFePO₄ cells with LTO-8 present a discharge specific capacity of 150 mAh g⁻¹ at 0.5C and a considerable average specific capacity of 119 mAh g⁻¹ under 5C in 400 cycles, demonstrating its excellent working performance. This investigation provides promising application of Li₄Ti₅O₁₂ for solid state electrolytes, which is superior to the reported solid state electrolytes in comprehensive performance, and surely paves another commercial way to solid state batteries.