Tree root-inspired structural electrolyte for laminated carbon fiber reinforced composites with high energy density and mechanically-robust properties

Abstract

Mechanically sturdy electrolytes with high ionic conductivity are the prerequisite for structural energy storage devices, which can store electrochemical energy and withstand mechanical loads, simultaneously. However, suitable structural electrolytes are rarely exploited. Herein, inspired by a tree root network, integrated with high ionic conductivity of poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF) based polymer and high mechanical strength of glass fiber fabric, the structural electrolyte GF/PVHF/KL-Z is designed and fabricated for structural Zn-ions batteries. The structural electrolyte demonstrates the ionic conductivity of 4.4*10-4 S cm−1 and excellent mechanical properties (110 MPa in tensile strength), enabling fast Zn2+ transmission and effective suppression of zinc dendrites. When carbon fiber reinforced laminated structural Zn-ion batteries were fabricated with structural electrolyte GF/PVHF/KL-Z, the structural devices delivered high mechanical strength (bending strength of 584.5 MPa) and energy density of 159.0 Wh kg−1. And after 500 cycles, the capacity retention of about 94.6% is also realized with Coulombic efficiency (CE) of nearly 100%. Importantly, the in situ mechanical-electrochemical tests further verify the multifunctional performance of the structural batteries. Overall, this work opens a pathway to developing safe, low-cost fiber reinforced biomimetic structural electrolytes for structural energy storage devices with excellent mechanical and electrochemical properties.