A strategy for enhancing Li-ion transport in quasi-solid polymer electrolytes using vinylene carbonate

Solid polymer electrolytes (SPEs), which offer advantages in film processing and flexibility for property regulation, have emerged as a promising strategy for Li-metal anodes. However, low ionic conductivity and a low Li⁺ transference number are well-known challenges for SPEs. To address these issues, we propose a novel approach for constructing a quasi-solid polymer electrolyte (QSPE) based on the polyvinylidene difluoride and polyvinyl acetate (PVDF/PVAC) polymer, incorporating vinylene carbonate (VC). Spectroscopic analyses and computational simulations demonstrate that the PVDF backbone of the QSPE accelerates the movement of the [Li⁺(VC)₃] complex. Due to this mechanism, exhibiting an ionic conductivity of 1.19 mS cm^-1, a Li-ion transference number of 0.74, and an activation energy of just 0.126 eV, the QSPE with VC shows promising characteristics. The Li//QSPE-VC//Li symmetric cell exhibits stable operation for more than 700 hours at a current density of 0.5 mA cm^-2, defaulting a capacity of 0.5 mAh cm^-2. The LFP//QSPE-VC//Li cell demonstrates a discharge capacity of 140.1 mAh g^-1 and retains 88% of its initial capacity after 650 cycles at 1C. The research in this article may contribute to the development of high-performance polymer electrolytes.