Enhancing Stability Pvdf-Hfp-Based Ternary Gel Electrolyte for Dendrite-Free Lithium Metal Anodes

Abstract

Lithium (Li) metal batteries hold great promise in high energy density rechargeable battery systems. However, Li metal anodes are poorly stable in liquid electrolytes and present safety risks. In this paper, we demonstrate that PVDF-HFP-based polymers have excellent electrolyte uptake (836.1%), which can form uniform gel electrolytes, fast Li+ transport channels, and ultra-long Li symmetric cycling. At a high current density of 5 mA cm-2, the gel electrolyte enables Li symmetric cells to achieve long cycling stability of 2700 h. At a current density of 2 C, a cell with LiCoO2 as the positive electrode achieved 2000 cycles with an average coulombic efficiency of around 99.5%, when applied to lithium-oxygen batteries, the lithium metal anode is also effectively protected, and the cycle life reaches 110 times, which provides new insights into the current pursuit of high power density batteries and fast charging technologies.

Keywords: Lithium (Li) metal batteries, High current density, Gel electrolyte, Long-term stable cycle