Colossal barocaloric effects in the complex hydride Li$$_{2}$$B$$_{12}$$H$$_{12}$$
Kartik Sau, Tamio Ikeshoji, Shigeyuki Takagi, Shin‐ichi Orimo, Daniel Errandonea, Dewei Chu, Claudio Cazorla
Abstract
Traditional refrigeration technologies based on compression cycles of greenhouse gases pose serious threats to the environment and cannot be downscaled to electronic device dimensions. Solid-state cooling exploits the thermal response of caloric materials to changes in the applied external fields (i.e., magnetic, electric and/or mechanical stress) and represents a promising alternative to current refrigeration methods. However, most of the caloric materials known to date present relatively small adiabatic temperature changes ([Formula: see text] to 10 K) and/or limiting irreversibility issues resulting from significant phase-transition hysteresis. Here, we predict by using molecular dynamics simulations the existence of colossal barocaloric effects induced by pressure (isothermal entropy changes of [Formula: see text] J K[Formula: see text] kg[Formula: see text]) in the energy material Li[Formula: see text]B[Formula: see text]H[Formula: see text]. Specifically, we estimate [Formula: see text] J K[Formula: see text] kg[Formula: see text] and [Formula: see text] K for a small pressure shift of P = 0.1 GPa at [Formula: see text] K. The disclosed colossal barocaloric effects are originated by a fairly reversible order-disorder phase transformation involving coexistence of Li[Formula: see text] diffusion and (BH)[Formula: see text] reorientational motion at high temperatures.