Multiscale Polyvinylidene Fluoride/Magnesium–Aluminum Layered Double Hydroxide Gel Electrolytes for Lithium Batteries

Abstract

A multiscale of porous polyvinylidene fluoride–hexafluoropropylene copolymer/magnesium–aluminum layered double hydroxides (MgAl‐LDHs) composite gel polymer electrolyte is prepared by phase separation method. It is discovered that the ionic conductivity of the electrolyte reaches a maximum value of 1.36 × 10−3 S cm−1, the lithium ions’ mobility is 0.66, and the chemical performance is steady within the 4.85 V window along with the concentration of MgAl‐LDHs up to 0.4 wt% at room temperature. The density functional theory calculations show that the adsorption energy of Li+ with MgAl‐LDH is −3.59 eV and the diffusion potential barrier is 0.37 eV, which is favorable for the dissociation and transport of Li+. Moreover, the anode's initial discharge capacity at 0.1 C achieves 144 mAh g−1, keeping 84.7% of the theoretical capacity of 170 mAh g−1, and the capacity retention and the columbic efficiency maintain 92.4% and 95.7% after 100 cycles at 0.2 C, respectively, through assembling into a Li/PVP–MgAl/LiFePO4 battery.