Biomimetic Fabrication of Multi-Scale Graphene Aerogel-Encapsulated Phase-Change Materials for Enhanced Thermal Energy Storage

Abstract

Phase change materials (PCMs) exhibit significant potential for thermal energy storage and thermal management applications. However, their practical implementation is limited by intrinsic challenges, including low thermal conductivity and leakage of liquid PCM. Aerogel encapsulation has emerged as an effective strategy to overcome these issues. Nevertheless, the disordered pore structure of conventional aerogels severely impedes thermal transport. Inspired by the leaf-vein architecture in nature, we report a multi-scale graphene/silver nanowire aerogel via directional freezing for PCM encapsulation. Benefiting from the synergistic effects of oriented networks and hydrogen-bonding interactions, the composite PCM (CPCM) exhibits a significantly enhanced thermal conductivity of 1.78 W·m–1·K–1 (a 514% increase compared to pure polyethylene glycol) and a high melting enthalpy (ΔHm = 150.9 J·g–1). The CPCM also demonstrates excellent shape stability, thermal stability, and cycling durability. Finite element analysis (FEA) simulations elucidate the influence of aerogel microstructure and thermal conductivity on phase transition dynamics, revealing that the optimized CPCM reduces energy storage time by approximately 60% compared to the unoptimized CPCM. By addressing the critical bottleneck of energy storage efficiency through a bio-inspired multiscale architecture, this study provides a promising avenue for the design of high-performance CPCMs for advanced energy storage applications.