Development of structural battery composites with high mechanical performance via extension of carbon fabric electrodes

Abstract

Structural battery composites (SBCs), which exhibit both electrical energy storage and mechanical load-bearing capabilities, have emerged as a prominent research focus in the field of lightweight and multifunctional materials. One of the primary challenges hindering the practical application of structural batteries is the inferior mechanical properties of most SBCs developed to date. To address this issue, a structure-level strategy was established to significantly enhance the mechanical performance by extending carbon fabric electrodes of the SBCs. Specifically, by selectively precuring the structural electrodes to facilitate encapsulation of the "battery part," the remaining outside regions of the fabric electrodes can be impregnated with polymer resin for effective loading transfer, resulting in greater stiffness compared to that of conventional SBCs. Scanning electron microscopy (SEM) was employed to characterize the interface between the active cathode material and the extended carbon fabrics. Furthermore, the electrochemical performance of SBCs with two different active material combinations but the same fabric extension strategy was evaluated, revealing high energy density of 19.8 Wh/kg based on total mass of the SBCs. In uniaxial tensile tests, the developed SBCs demonstrated exceptional ultimate tensile strength and Young's modulus of 401.1 MPa and 43.8 GPa, respectively. Additionally, under bias-extension loading, shear yield strength of 17.1 MPa and shear modulus of 2.17 GPa were achieved. These results collectively contribute to excellent multifunctional efficiency, with the maximum value of 1.59. This work promotes the development and practical deployment of structural batteries, particularly for applications in highly demanding load-bearing scenarios.