Sub-minute synthesis and modulation of β/λ-M_xTi_3-xO₅ ceramics towards accessible heat storage

Nearly 50% of global primary energy consumption is lost as low-temperature heat. λ-Ti₃O₅ holds promise for waste heat harvesting and reuse; however, achieving reversible phase transitions between its λ and β phases under accessible conditions remains a major challenge. Here, we proposed a simple laser method that incorporates element substitution for sub-minute synthesis (20-60 s) of λ-M_xTi_3-xO₅ (M = Mg, Al, Sc, V, Cr, Mn, or Fe, 0.09 ≤ x ≤ 0.42). In particular, aluminum-substituted λ-Al_xTi_3-xO₅ demonstrated the lowest energy barrier, with a transition pressure of 557 MPa and temperature of 363 K. Notably, compression of the (001) crystal plane could reduce the transition pressure to only 35-40 MPa, enabling the applicability of λ-Al_xTi_3-xO₅ for wide applications in heat recovery and future lunar explorations.