Development and use of geopolymers for energy conversion: An overview

The use of geopolymers for energy conversion is revised in this work, focusing on the conductive properties, Seebeck and piezoelectric effects. The effect of semi-conductive materials such as TiO2 and carbon-based materials, and alkaline activator concentrations on geopolymers are presented and discussed. Also, the piezoelectric effects on geopolymer were emphasized when graphene and TiO2 were used as fillers. Research findings revealed that geopolymers exhibited a piezoelectric effect after being compressed cyclically, which increased by incorporating graphene nanoplatelets or semiconductors. Geopolymers with TiO2 have photoactivity in addition to the ionic conductivity capacity, while carbon-based materials increase the conductivity of composites and create three-dimensional networks of connectivity into geopolymer. These findings are discussed as well as the trends in the exciting area of solar, thermal, and mechanical energy conversion using geopolymers, an attractive material for building.