External stimulation-controllable heat-storage ceramics

• Published in: Nature communications Vol. 6; no. 1; p. 7037
• Main Authors: Tokoro, Hiroko, Yoshikiyo, Marie, Imoto, Kenta, Namai, Asuka, Nasu, Tomomichi, Nakagawa, Kosuke, Ozaki, Noriaki, Hakoe, Fumiyoshi, Tanaka, Kenji, Chiba, Kouji, Makiura, Rie, Prassides, Kosmas, Ohkoshi, Shin-ichi
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 12.05.2015; Nature Pub. Group
• Subjects: Crystal structure; Electric currents; Electrons; Fourier transforms; Heat; Light; Materials science; Maximum entropy method; Microscopy; Morphology; Phase transitions; Thermal energy; Japan
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms8037

Commonly available heat-storage materials cannot usually store the energy for a prolonged period. If a solid material could conserve the accumulated thermal energy, then its heat-storage application potential is considerably widened. Here we report a phase transition material that can conserve the latent heat energy in a wide temperature range, T<530 K and release the heat energy on the application of pressure. This material is stripe-type lambda-trititanium pentoxide, λ-Ti3O5, which exhibits a solid-solid phase transition to beta-trititanium pentoxide, β-Ti3O5. The pressure for conversion is extremely small, only 600 bar (60 MPa) at ambient temperature, and the accumulated heat energy is surprisingly large (230 kJ L(-1)). Conversely, the pressure-produced beta-trititanium pentoxide transforms to lambda-trititanium pentoxide by heat, light or electric current. That is, the present system exhibits pressure-and-heat, pressure-and-light and pressure-and-current reversible phase transitions. The material may be useful for heat storage, as well as in sensor and switching memory device applications.