Utilization of renewable energy such as solar, wind, and geothermal power, appears to be the most promising solution for the development of sustainable energy systems without using fossil fuels. Energy storage, especially to store the energy from fluctuating power is quite vital for smoothing out energy demands with peak/off-peak hour fluctuations. Thermal energy is a potential candidate to serve as an energy reserve. However, currently the development of thermal energy storage (TES) by traditional physical means is restricted by the relatively low energy density, high temperature demand, and the great thermal energy loss during long-period storage. Chemical heat storage is one of the most promising alternatives for TES due to its high energy density, low energy loss, flexible temperature range, and excellent storage duration. A comprehensive review on the development of different types of Mg-based materials for chemical heat storage is presented here and the classic and state-of-the-art technologies are summarized. Some related chemical principles, as well as heat storage properties, are discussed in the context. Finally, some dominant factors of chemical heat storage materials are concluded and the perspective is proposed for the development of next-generation chemical heat storage technologies.

Here we report a Ti₅₀V₅₀-10 wt.% C alloy with a unique lattice and microstructure for hydrogen storage development. Different from a traditionally synthesized Ti₅₀V₅₀ alloy prepared by a melting method and having a body-centered cubic (BCC) structure, this Ti₅₀V₅₀-C alloy synthesized by a mechanical alloying method is with a face-centered cubic (FCC) structure (space group: Fm-3m No. 225). The crystalline size is 60 nm. This alloy may directly absorb hydrogen near room temperature without any activation process. Mechanisms of the good kinetics from lattice and microstructure aspects were discussed. Findings reported here may indicate a new possibility in the development of future hydrogen storage materials.