External stimulation-controllable heat-storage ceramics.

Most heat-storage materials available today cannot retain thermal energy for extended durations, limiting their practical use. While latent heat storage systems are known, they often lack control over energy release. Prior research has shown that solid-state phase transitions can store energy, but few materials allow for on-demand energy release. The ability to control energy conservation and release remains a key challenge in thermal storage. No prior work had resolved how to trigger energy release using external stimuli like pressure or light. This gap motivated the search for a material that could store and release heat energy controllably. Researchers have explored various ceramics and oxides, but none combined heat storage with reversible phase transitions. The need for a material that can store thermal energy and release it upon external stimulation remains unmet. This study addresses that need by introducing a novel phase transition material.

The study aimed to develop a material capable of storing thermal energy over a wide temperature range and releasing it upon external stimulation. The researchers sought a system that could transition between phases using minimal pressure and return to its original state via heat, light, or electricity. The goal was to create a material that could function as a heat-storage medium with controllable energy release. The specific problem addressed was the lack of materials that allow for both energy conservation and on-demand release. Researchers wanted to design a system that could reversibly switch between two stable solid phases. The motivation was to expand the potential applications of heat-storage materials beyond passive systems. By introducing a pressure-triggered phase transition, the team aimed to enable controlled energy release. The study also aimed to explore the material's potential for use in sensors or memory devices.

The study focused on stripe-type lambda-trititanium pentoxide, λ-Ti₃O₅, as the candidate material. The researchers examined its solid-solid phase transition to beta-trititanium pentoxide, β-Ti₃O₅, under pressure. They applied a pressure of 600 bar at room temperature to induce the phase change. The team measured the latent heat stored during the transition and observed the energy density of 230 kJ L⁻¹. They also tested the reverse transition using heat, light, and electric current as stimuli. The researchers analyzed the material's structural changes using spectroscopic and diffraction techniques. They evaluated the material's stability and reversibility over multiple cycles. The study combined experimental characterization with theoretical modeling of the phase transitions.

The material stored a large amount of latent heat, reaching 230 kJ L⁻¹. The phase transition from λ-Ti₃O₅ to β-Ti₃O₅ occurred at a low pressure of 600 bar. The transition was fully reversible, with β-Ti₃O₅ reverting to λ-Ti₃O₅ upon exposure to heat, light, or electricity. The system demonstrated pressure-and-heat, pressure-and-light, and pressure-and-current reversible transitions. The material remained stable across multiple cycles of phase changes. The energy storage capacity was significantly higher than that of conventional materials. The low-pressure requirement made the system practical for real-world applications. The material's ability to store and release energy controllably suggests broad applicability.

The material λ-Ti₃O₅ can store thermal energy and release it upon external stimulation. The phase transition occurs at a low pressure of 600 bar and is fully reversible. The system supports multiple stimuli for energy release, including heat, light, and electricity. The material's energy storage capacity is notably high at 230 kJ L⁻¹. The findings suggest that the material could be useful in heat storage applications. The system also shows potential for use in sensors and memory devices. The researchers propose that the material's controllable energy release mechanism may expand its utility. The study highlights the material's stability and reversibility over multiple cycles.