Observation of a Pressure Effect on an Al-substituted λ-Ti3O5 Heat-storage Material

Abstract We report a pressure effect on a heat-storage material, Al-substituted lambda-trititanium-pentoxide (λ-AlxTi3−xO5, 0 < x ≤ 0.29), showing a phase transition to β-AlxTi3−xO5 by pressure application. The transition pressure is 23 MPa and 43 MPa for x = 0.01 and 0.04, respectively, which are available pressures for practical applications. First-principles electronic structure calculations of λ-Al0.25Ti2.75O5 were conducted to investigate the substitution site selectivity of the Al3+ ion and the substitution effect on the pressure-induced phase transition.