  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 external fields and represents a
promising alternative to current refrigeration methods. However, most of the
caloric materials known to date present relatively small adiabatic temperature
changes ($|\Delta T| \sim 1$ K) and/or limiting irreversibility issues
resulting from significant phase-transition hysteresis. Here, we predict the
existence of colossal barocaloric effects (isothermal entropy changes of
$|\Delta S| \sim 100$ JK$^{-1}$kg$^{-1}$) in the energy material
Li$_{2}$B$_{12}$H$_{12}$ by means of molecular dynamics simulations.
Specifically, we estimate $|\Delta S| = 387$ JK$^{-1}$kg$^{-1}$ and $|\Delta T|
= 26$ K for an applied pressure of $P = 0.4$ GPa at $T = 475$ K. The disclosed
colossal barocaloric effects are originated by an order-disorder phase
transformation that exhibits a fair degree of reversibility and involves
coexisting Li$^{+}$ diffusion and (BH)$_{12}^{-2}$ reorientational motion at
high temperatures.
