Electrochemical Performance of a PVDF-HFP-LiClO₄-Li_6.4La_3.0Zr_1.4Ta_0.6O₁₂ Composite Solid Electrolyte at Different Temperatures

Abstract

The stability and wide temperature performance range of solid electrolytes are the keys to the development of high-energy density all-solid-state lithium-ion batteries. In this work, a PVDF-HFP-LiClO4-Li6.4La3Zr1.4Ta0.6O12 (LLZTO) composite solid electrolyte was prepared using the solution pouring method. The PVDF-HFP-LiClO4-LLZTO composite solid electrolyte shows excellent electrochemical performance in the temperature range of 30 to 60 °C. By assembling this electrolyte into the battery, the LiFePO4/PVDF-HFP-LiClO4-LLZTO/Li battery shows outstanding electrochemical performance in the temperature range of 30 to 60 °C. The ionic conductivity of the composite electrolyte membrane at 30 °C and 60 °C is 5.5 × 10−5 S cm−1 and 1.0 × 10−5 S cm−1, respectively. At a current density of 0.2 C, the LiFePO4/PVDF-HFP-LiClO4-LLZTO/Li battery shows a high initial specific discharge capacity of 133.3 and 167.2 mAh g−1 at 30 °C and 60 °C, respectively. After 50 cycles, the reversible electrochemical capacity of the battery is 121.5 and 154.6 mAh g−1 at 30 °C and 60 °C; the corresponding capacity retention rates are 91.2% and 92.5%, respectively. Therefore, this work provides an effective strategy for the design and preparation of solid-state lithium-ion batteries.

Keywords

• lithium-ion battery
• solid-state electrolyte
• composite
• electrochemical performance