Enhancing the thermal cyclic reliability of salt-based shape-stabilized phase change materials by in-situ SiO2–C interconnectivity in rice husk carbon

Abstract

Utilizing salt-based shape-stabilized phase change materials (ss-PCMs) for high-temperature thermal energy storage stands as a pivotal avenue in realizing carbon neutrality. However, the performance of ss-PCMs significantly deteriorates after thermal cycling. This study utilizes rice husk carbon (RHC) with an in-situ SiO2–C interconnected structure as the encapsulating material, along with expanded graphite (EG) and MgO, to encapsulate ternary chloride (TC). In this approach, RHC simultaneously acts as a thermal conductivity materials (TCM) and a ceramic supporting material (CCM). The results showed that this encapsulation method can effectively encapsulate up to 65% of TC. The 60 wt% TC-10 wt% RHC-10 wt% EG-20 wt% MgO sample named 60T/10R/10E/20M is considered a close to optimal formulation in terms of thermal conductivity and phase change enthalpy. This ss-PCM has a thermal conductivity of 8.86 W m−1 K−1, and phase change enthalpy of 153.6 J g−1. The ss-PCMs maintained shape stability even after 1000 cycles, with minimal mass loss and thermal conductivity degradation compared to the non-RHC-added ss-PCM. This study has prepared high performance and reliability thermal storage materials through a green and low-cost approach.