Construction of metal organic framework-derived hollow-structured mesoporous carbon based lithium hydroxide composites for low-grade thermal energy storage

Benefiting from its remarkable storage capacity and long energy preservation life-span, salt hydrate thermochemical energy storage (TCES) materials build a passable bridge between renewable energy and residential heating. To the best of our knowledge, the application of carbon matrix derived from metal organic frameworks (MOFs) in TCES have not been reported so far. Herein, a brand new LiOH TCES composite with salt hydrate uniformly dispersed in an activated hollow carbon (AHC) with a hollow mesoporous structure derived from the hollow zeolite imidazolate framework is prepared and fully characterized. The resulting Li/AHC2 composite is equipped with excellent hydration performance while exhibiting a maximum heat storage capacity of 1757.1 kJ kg −1 with low working temperature owing to the synergistic effect of cavity structure, large surface area and diversified porosity of AHC2. Besides, compared with pure LiOH, the Li/AHC2-50 with significantly enhanced thermal conductivity can still maintain 90.2% of the original heat storage capacity after 15 dehydration-hydration cycles, highlighting its outstanding fatigue resistance and huge heat transfer application potential. This study not only becomes a new dawn for the effective use of available low-temperature heat sources, but may also inspire new thoughts for expanding the implementation territory of carbon materials derived from MOFs. • MOF-derived porous carbon material was first applied to the field of chemical heat storage as a host matrix. • The host matrix AHC2 integrates the advantages of cavity structure, ultrahigh specific surface area and diversified porosity. • Li/AHC2 composites show high heat storage density with low working temperature and outstanding hydration performance. • Li/AHC2-50 composite exhibits great fatigue resistance and remarkable thermal conductivity.