Mussel-Inspired Phase Change Composites Utilizing Three-Dimensional Interpenetrating Silver Particle Networks within Biomass/Polymer Waste for Enhanced Thermal Management, Photothermal Energy Storage, and Electrothermal Conversion of Lithium Ions

Abstract

Flexible Phase Change Materials (PCMs) are cost-effective, widely produced, and offer high energy storage density, degradability, and thermal conductivity. These properties make them crucial for practical applications in thermal management. In this study, we utilized inexpensive cotton as a template to construct biomass-derived three-dimensional (3D) carbon scaffolds containing polydopamine (PDA) and silver nanoparticles (AgNPs). We then prepared CCPAX@PW flexible PCMs by encapsulating paraffin wax (PW). PDA was chosen to enhance the interface bonding between the fiber and AgNPs. A continuous network of AgNPs wrapped around a cotton fiber skeleton forms a 3D heat-conductive cross-linked structure. Compared to C@PW, the thermal conductivity of CCPAX@PW increased nearly ninefold, and the enthalpy of melting for CCPA30@PW reached 135.05 J/g. The use of a 3D conducting AgNPs network resulted in extremely high electrical conductivity for CCPAX@PW, with CCPA90@PW reaching 186.6 S/m. This significantly improved the joule heating rate. Simultaneously, the photothermal conversion efficiency and electrothermal conversion efficiency were 75.6% and 85.6%, respectively. Furthermore, the flexible PCM demonstrated a 100% encapsulation efficiency at high temperatures, addressing the brittleness issue of previous phase change materials and preventing PW leakage. This advancement broadens its practical applications. Notably, we found that wrapping lithium-ion batteries with CCPAX@PW PCM significantly reduced their surface temperature, extending battery lifespan and reducing the risk of spontaneous combustion. In the future, this flexible PCM holds great potential for efficient energy storage and conversion, as well as thermal management of batteries.

Keywords: Phase change, Biomass, Energy conversion, Flexibility, Scaffolds