Long‐Term Heat‐Storage Ceramics based on Zr‐Substituted λ‐Ti 3 O 5

Heat‐storage materials are important for energy saving to protect the environment. Here, we show a long‐term heat‐storage material based on zirconium‐substituted lambda‐trititanium‐pentoxide (λ‐Zr x Ti 3− x O 5 , 0 < x ≤0.06). λ‐Zr x Ti 3− x O 5 exhibits a phase transition to zirconium‐substituted beta‐trititanium‐pentoxide (β‐Zr x Ti 3− x O 5 ) upon application of pressure. The transition pressures were 600 MPa ( x =0.04) and about 1 GPa ( x =0.06). When the pressure‐produced β‐phase is heated, the β‐phase returns to λ‐phase. The phase transition temperatures (i. e., heat‐storage temperatures) were 185 °C (458 K) and 183 °C (453 K) for x =0.04 and 0.06, respectively. These heat‐storage temperatures are suitable for the reuse of low‐temperature industrial waste heat, which is considered to be a difficult temperature region to be efficiently collected and reused. The present pressure‐sensitive heat‐storage ceramic, which can store the latent heat energy for a prolonged period, is effective for the sustainable reuse of heat energy that are wasted in power plants and industrial factories.