In‐situ Construction of Poly(tetraisopentyl acrylate) based Gel Polymer Electrolytes with LixLa2‐xTiO3 for High Energy Density Lithium‐Metal Batteries

As promising alternatives to liquid electrolytes, polymer electrolytes attract much research interest recently, but their widespread use is limited by the low ionic conductivity. In this study, we use electrostatic spinning to introduce particles of an ionic conductor into polyacrylonitrile (PAN) fibers to prepare a porous membrane as the host of gel polymer electrolytes (GPEs). The relevant in‐situ produced GPE performs a high ionic conductivity of 6.0×10−3 S cm−1, and a high lithium transfer number (tLi+) of 0.85 at 30 °C, respectively. A symmetrical Li cell with this GPE can cycle stably for 550 h at a current density of 0.5 mA cm−2. While the capacity retention of the NCM|GPE|Li cell is 79.84 % after 500 cycles at 2 C. Even with an increased cut‐off voltage of 4.5 V, the 1st coulomb efficiency reaches 91.58 % with a specific discharge capacity of 213.4 mAh g−1. This study provides a viable route for the practical application of high energy density lithium metal batteries. The LLTO‐containing PAN was prepared by electrostatic spinning as a polymer matrix, which was subsequently used to prepared gel polymer electrolyte by in‐situ polymerization. The obtained gel polymer electrolyte has a high ionic conductivity and lithium‐ion transference number, which assembles to form a high energy density lithium metal battery with excellent performance.