Giant barocaloric effects in natural graphite/polydimethylsiloxane rubber composites

Solid-state cooling based on caloric effects is considered a viable alternative to replace the conventional vapor-compression refrigeration systems. Regarding barocaloric materials, recent results show that elastomers are promising candidates for cooling applications around room temperature. However, elastomers are insulating materials, which is a disadvantage that may compromise practical applications, since high heat transfer properties are typically desirable for more efficiency. Herein, barocaloric effects are investigated in natural graphite/polydimethylsiloxane rubber composites (NG/PDMS), in different concentrations of natural graphite. Adding natural graphite to PDMS, the adiabatic temperature change and the isothermal entropy change of the NG/PDMS composites reduce when compared to PDMS, but the composites still remain in giant barocaloric class and achieve an increase up to ~ 500% in thermal diffusivity and thermal conductivity. The results are promising for solid-state cooling based on barocaloric effect because the NG/PDMS composites combine different desired properties and are identified as better or similar among different barocaloric materials reported in the literature. Graphical abstract