Biomass waste lotus shell-based shape-stabilized phase change composites with improved thermal conductivity for thermal management

Abstract

Lotus shells represent an underutilized renewable resource with desirable porous architecture for producing bio-based phase change composites (PCMs). This research endeavors to fabricate a series of shape-stable phase change composites (SSPCCs) based on n-docosane (ND) and waste lotus shells to enhance heat utilization, solar photothermal energy conversion, and promote environmental protection. Both carbonization and activation processes play a critical role in the formation of desired pore structures. The carbonized lotus shells (CLS) and activated lotus shells (ALS) exhibit superior specific surface areas, reaching 147.70 m2/g for CLS and 1652.35 m2/g for ALS. Notably, the composite of ND integrated with ALS (ND/ALS) exhibits satisfactory latent heat storage of 93.68 J/g, excellent leakage prevention, and exceptional thermal cycle stability. Subsequently, the ND/ALS displays a significantly enhanced thermal conductivity of 0.482 W/(m·K) with an appreciable increment of 189% compared to ND. Furthermore, the obtained SSPCCs present good chemical compatibility, satisfactory thermochemical stability, and outstanding thermal management capability. In conclusion, the novel waste lotus shell-derived SSPCCs exhibit extensive potential for thermal management, such as heat recovery, solar energy conversion, and temperature regulation. This research not only introduces a promising avenue for enhancing sustainable materials in energy storage and conversion but also pioneers an innovative recycling strategy for waste lotus shells, thereby contributing to both environmental sustainability and efficient resource utilization.