A buffering PVDF-HFP-based gel polymer electrolyte for stable and flexible lithium batteries

Abstract

Flexible lithium batteries (FLBs) are highly regarded as potential candidates for next-generation batteries due to their versatility in various applications. However, the main focus in the development of FLBs lies in addressing mechanical challenges such as crack propagation under conditions of flexibility and stretchability. Herein, this work presents a novel design of a gel polymer electrolyte (GPE112) film prepared by solution-casting methods. The GPE112 film shows high ion conductivity of 2.12 × 10⁻⁴ S cm⁻¹, a window voltage stability of ∼4.6 V, and compatibility with various commercial cathodes such as LiFePO₄, LiCoO₂ and LiNi_0.8Co_0.1Mn_0.1O₂. On the other hand, the mechanically robust GPE112 film exhibits elongation at break of ∼41%, making it a potentially superior alternative to a commercial polypropylene (PP) separator. Furthermore, through finite element method (FEM) simulation, the utilization of a hot-pressed polymer electrolyte in conjunction with a cathode active layer demonstrates the potential to mitigate crack propagation and prevent delamination, leading to the development of flexible batteries with robust structures. Generally, the investigation demonstrates that the prepared GPE112 film provides potential application in safe FLBs no matter the electrochemical or mechanical properties.