Enhanced Li+ transport path and interface stability of multi-channel hollow Li0.33La0.557TiO3 reinforced PVDF-based electrolytes

Abstract

Solid-state batteries and electrolytes are considered one of the excellent options for next-generation battery technology due to reliable safety and high energy density. The polymer-inorganics composite electrolytes were prepared by combining the multi-channel hollow Li_0.33La_0.557TiO₃ (MCH-LLTO) with poly(vinylidene fluoride) (PVDF). MCH-LLTO electrolytes were synthesized to effectively improve the large Li⁺ transport path. Compared with the pure PVDF, the high room-temperature ionic conductivity of 4.6 $\times$ 10⁻⁴ S/cm² approached for PVDF/MCH-LLTO-40 composite electrolyte. By forming the hybrid interface in PVDF matrix, the large Li⁺ transference number was 0.74 and the electrochemical stability exhibited during long-term cycling of 1400 h. Moreover, the initial discharge capacity and the coulomb efficiency were 147.3 mAh·g⁻¹ and 99.27 % under 0.2C were obtained. After 100 cycles, the capacity of 130 mAh·g⁻¹ maintained and the coulomb efficiency was 99.59 %, with a capacity retention rate of 86 %. This work proves that the MCH-LLTO fillers can provide the large Li⁺ transporting path and boost electrochemical performance in organic-inorganic composite electrolytes.