Localized iodinated poly (Vinylidene Difluoride)-based solid-state electrolyte for enhanced dendrite-free lithium metal batteries

Abstract

Background

Addressing the challenges of solid-state batteries in the new energy sector requires a focus on interface issues. The interface between the solid electrolyte and the lithium metal anode is crucial, as it significantly influences battery performance.

Methods

Iodine-introduced poly (vinylidene fluoride) (PVDF) solid electrolytes are synthesized by solution casting method. The electrolyte is found to form a stable LiI-containing and LiF-rich interface with the lithium metal anode by sputtering XPS.

Significant findings

The acquired electrolytes show outstanding lithium-ion conductivity (7.9 × 10⁻⁴ S cm⁻¹) and migration number (0.42). The Li || Li batteries with the proposed electrolyte can cycle stably for 1000 h at a current density of 0.1 mA cm⁻², the LFP || Li batteries maintain up to 97.2 % capacity retention at 0.5C after 1000 cycles, and 98.7 % capacity retention at 1C after 300 cycles. A pouch cell with the solid polymer electrolyte is able to undergo stably for >200 cycles at 0.5C.