Biochar Shape-Stabilized Phase-Change Materials for Thermal Energy Storage

Biochar is the black fine-grained residue of the pyrolysis of biomass. It is the product of a thermochemical decomposition at moderate temperatures under oxygen-limiting conditions. This residue has a pore structure with large specific surface area, accompanied by a strong adsorption capacity. Due to the presence of a mesoporous framework, biochar can be used to shape-stabilize phase-change materials (PCMs), which are substances absorbing and releasing thermal energy at phase transitions. Biochar is overcoming the leakage problem of PCMs, by encapsulating their liquid phases in the pores. Consequently, biochar and PCMs, in particular the organic PCMs, can be used to produce eco-friendly stable composites, which can be useful for heating and cooling applications. Here we propose a discussion of recent literature about development and applications of biochar-based composite PCMs. In particular, the literature about the role of biochar mesopores in the encapsulation of PCM is highlighted.