Thermal conductivity and cycle characteristic of metal hydride sheet formed using aramid pulp and carbon fiber

This paper describes the thermal and hydrogenation properties of a metal hydride (MH) sheet consisting of MH powder, aramid pulp, and carbon fiber. MH sheets were prepared by the wet paper method in which an agglutinated slurry of raw materials was dispersed onto a stainless steel mesh in water and then the sheet was dehydrated and dried. The cyclic characteristics and thermal conductivities of the MH sheets were experimentally investigated. The effects of changing the carbon fiber ratio and the measurement direction on the effective thermal conductivity were measured by the steady heat flow method. The thermal conductivity increased to 3.20 W/m·K with increasing carbon fiber ratio only in the planar direction. The decreases in mass due to removing MH powder and/or carbon fiber from sheet were less than 1 mass% after around 100 hydrogen absorption/desorption cycles. Moreover, the MH sheet was effective at decreasing the stress on the reactor vessel due to the expansion of MH during hydrogen absorption/desorption.

► We developed metal hydride (MH) sheet formed using MH, aramid, and carbon fiber (CF).
► The MH sheet formed with 30 mass% of CF showed 3.20 W/m·K in the planar direction.
► The MH sheet did not limit the mass transfer of hydrogen to the MH surface.
►  Decrease in mass due to removing MH from sheet were less than 1% after 100 cycles.
► The packing fraction of an MH packed-bed could be controlled using an MH sheet.