Supercooled Liquids in a Core-Shell Coordination Structure for Practical Long-Term Energy Storage.

Area of Science:

• Materials Science
• Chemistry

Background:

• Phase-change materials are crucial for energy storage, but achieving both phase-stability and controllable phase-transitions remains a challenge.
• Existing materials often struggle to balance long-term stability with reversible phase-transition properties.

Purpose of the Study:

• To develop a novel phase-change material that simultaneously possesses thermal phase-stability and controllable, reversible phase-transition.
• To address the contradictory demands for practical long-term energy storage applications.

Main Methods:

• A core-shell structure was engineered, combining coordination bonds in the core and hydrogen bonds in the shell.
• The material consists of a manganese-methylurea (MM) complex core and a hierarchically bonded erythritol shell.
• Ligand-exchange reactions were utilized to trigger reversible phase-transitions.

Main Results:

• The developed material exhibits excellent thermal phase-stability, attributed to the high viscosity (10^8 Pa·s) of the MM glass core.
• An effective and reversible phase-transition was achieved, triggered by a low shear-stress (10 Pa) within tens of seconds.
• The mechanism involves an ingenious ligand-exchange between erythritol and chloride ions coordinated with the MM core.

Conclusions:

• The hierarchical combination of coordination and hydrogen bonds in a core-shell structure successfully reconciles phase-stability and controllable phase-transition.
• This new material demonstrates significant potential for practical long-term energy storage applications due to its stability and triggered reversibility.