(Invited) Three-Dimensional Filter of Polyvinylidene Difluoride (PVDF) Implanted Rice Husk-Derived Silicon Dioxide of Porous Solid-State Electrolytes

Abstract

Lithium-ion batteries are the most promising energy storage devices in the battery technology field. They are widely used for numerous advantages, such as high energy density, fast charging, and being environmentally friendly. Lithium metal as an anode is highly attractive among different electrode materials because of its extraordinarily high specific capacity. However, lithium metal is prone to form dendrites during the battery charging process. Unfortunately, the conventional battery composed of flammable organic liquid electrolytes fails to suppress the lithium dendrite formation. The lithium dendrite thus penetrates the separator, causing battery short and bringing about explosions and catastrophes. Solid-state electrolytes (SSEs) have recently attracted much attention due to their higher energy density, wide electrochemical stability window, and longer cycle life. In addition, SSEs are mechanically more robust, suppressing the lithium dendrites formation. Therefore, replacing liquid electrolytes with solid-state electrolytes is an effective strategy to resolve safety concerns. To increase the mechanical strength of the SSEs, in this work, we report a three-dimensional filter-network-reinforced SSEs with a porous polyvinylidene difluoride (PVDF) filter host, polyethylene glycol (PEG) matrix with bistrifluoromethanesulfonimide lithium salt (LiTFSI) and rice husk-derived silicon dioxide (RHSiO2) as a passive filler. Rice husk-derived silicon dioxide possesses many superiorities, such as low-cost, easy processing, and non-toxicity. The mechanically robust PVDF filter helps to improve the mechanical property (tensile strength > 5 MPa) and prevents dendrite penetration, which raises thermal and mechanical stability. At room temperature, the ionic conductivity of the 5wt% SSE reach 1.110-4 S cm-1. The battery with 5wt% RHSiO2 SSE enabled stable cycling for over 300 hr during the Li plating and stripping process, demonstrating that the PVDF filter host SSEs with RHSiO2 is promising for the high-safety energy storage systems.