Reduced graphene oxide/calcium alginate/polyethylene glycol composite phase change material with double-network structure for enhanced photothermal conversion

Abstract

Phase change materials (PCMs) are widely used in thermal energy storage and temperature regulation due to their ability to absorb and release latent heat during phase transitions. However, conventional PCMs often suffer from leakage and low thermal conductivity, which significantly limits their practical applications. Although polymer networks have been employed to encapsulate PCMs, challenges such as lack of functional modification, complex processing steps and high production costs still need to be resolved. We presented a strategy for synthesizing a double-network composite phase change material through the in situ self-assembly of graphene oxide (GO) within a sodium alginate (SA) matrix, combined with ionic crosslinking between SA and Ca²⁺, resulting in a reduced graphene oxide/calcium alginate/polyethylene glycol (RGO/CA/PEG) composite phase change material. CA imparted good dispersibility to RGO under the premise of effective encapsulation of PEG, and reduced the pressure of RGO encapsulation, resulting in a significant reduction in the preparation cost of the material. The results show that the RGO/CA/PEG has a high energy storage density (145.54 J/g) and can be maintained at 70 °C for 6 h without any leakage. Meanwhile, the construction of the RGO/CA double network enabled the PEG to have good thermal conductivity (127.78 % improvement over pure PEG) and photothermal conversion (85.54 %). The above studies show that the material has good application prospects for solar energy harvesting, battery thermal management, and thermal energy storage.