High-Entropy Functional Materials for Extreme-Environment Energy Storage and Aerospace Applications: A Review

Abstract

ABSTRACT The progression of space exploration, hypersonic flight, and polar deployment demands energy storage and thermal management systems capable of uncompromised performance under severe operational stressors. Conventional energy storage materials suffer severe structural degradation, phase transitions, voltage decay, and thermal runaway when subjected to cryogenic extremes below -60°C, ultra-high temperatures exceeding 1000°C, ionizing radiation, and severe mechanical shock. High-entropy functional materials (HEFMs), including multi-principal element high-entropy oxides (HEOs), high-entropy diborides (HEBs), high-entropy MXenes, and high entropy solid electrolytes, have emerged as a disruptive paradigm to overcome these thermodynamic and kinetic limitations. By leveraging high configurational entropy (?S_config ? 1.5R), sluggish diffusion kinetics, lattice distortion, and cocktail effects, HEFMs demonstrate structural stability, enhanced ionic transport via engineered oxygen vacancies, robust radiation tolerance, and mechanical toughness across broad thermal envelopes. This review synthesizes recent breakthroughs in the design, synthesis, and application of HEFMs for extreme-environment energy storage systems, specifically solid-state batteries, high-temperature supercapacitors, and aerospace thermal-electrochemical units. We evaluate thermodynamic mechanisms governing entropy stabilization, examine synthesis microstructure-property relationships across architectures, and quantify performance metrics under simulated space environments. Key research gaps regarding long-term phase stability under extreme thermal cycling, interface degradation dynamics, and scalable manufacturing are identified. Strategic pathways for machine learning discovery and space-qualification protocols are outlined to transition high-entropy energy materials into mission-critical aerospace platforms.

KEYWORDS: High-entropy functional materials; Energy storage; Aerospace applications; Solid-state batteries; Extreme thermal environments; Entropy stabilization; Supercapacitors.