  Nowadays the world is facing a prominent paradox regarding thermal energy.
The production of heat accounts for more than 50% of global final energy
consumption while the waste heat potential analysis reveals that 72% of the
global primary energy consumption is lost after conversion mainly in the form
of heat. Towards global decarbonization, it is of vital importance to establish
a solution to thermal energy utilization under full control. Here, we propose
and realize an unprecedented concept -- barocaloric thermal batteries based on
the inverse colossal barocaloric effect of NH4SCN. Thermal charging is
initialized upon pressurization through an order-to-disorder phase transition
below 364 K and in turn the discharging of 43 J g-1, which are eleven times
more than the input mechanical energy, occurs on demand at depressurization at
lower temperatures. The discharging is also manifested as a directly measured
temperature rise of 12 K. The thermodynamic equilibrium nature of the
pressure-restrained heat-carrying phase guarantees stable storage and/or
transport over a variety of temporal and/or spatial scales. The barocaloric
thermal batteries reinforced by their solid microscopic mechanism are expected
to significantly advance the ability to take advantage of waste heat.
