A New Insight Into the Multifunctional Property Balance of the Carbon Fiber Reinforced Energy Storage Composites Containing Dual‐Phase Electrolyte Matrices Accounting for the Compressive Strength

ABSTRACT Carbon fiber reinforced energy storage composites (CFRESCs) can integrate structural load‐bearing and energy storage functions. However, the introduction of functional electrolyte phases usually weakens their compressive performance. Especially for CFRESCs with biphasic electrolyte matrices, the compressive behavior has not yet been systematically understood. To address this issue, a multiscale framework is developed to quantify the influence of functional phase (FP) content in dual‐phase electrolyte matrices on the compressive performance of unidirectional CFRESCs. First, a representative volume element (RVE) model was constructed according to the Cahn–Hilliard phase separation equation to characterize the microstructure features of the material. Subsequently, the nonlinear shear response of the material was extracted and fitted using the Ramberg–Osgood (RO) model; the obtained parameters were incorporated into the compressive failure model based on the micro‐buckling theory to predict the macroscopic compressive strength. The results showed that there is a clear trade‐off relationship between compressive strength and FP content. Increasing the matrix modulus and reducing the hardening exponent of the unidirectional composite can effectively enhance the compressive strength. The model prediction results were in good agreement with the experimental data. In conclusion, this study provides a mechanistic understanding and reference prediction tools for optimizing the compression performance of CFRESCs and achieving a balanced design of mechanical and functional properties.