Enhancing comprehensive performance of epoxy-based sealing layer with a binary nanofiller for underground hydrogen energy storage

Underground hydrogen energy storage (UHES) placing higher demands on the mechanical property, thermal conductivity and gas barrier capacity of the sealing materials. In this study, binary nanofillers consisting of impermeable graphene oxide (GO) and highly thermally conductive aluminum oxide (AO) linked by 4,4 '- diphenylmethane diisocyanate (MDI) are incorporated. Composite sealing layers with varying mass fractions (Mf) of binary nanofillers are prepared using in situ polymerization with epoxy (EP) as matrix. Results show that the ultimate displacement, thermal conductivity and gas barrier capacity of the composite sealing layers increased with increasing Mf of binary nanofillers. The optimized composite sealing layer with 10 % Mf of binary nanofillers demonstrated sult and lambda values of 28.54 mm and 0.35 Wm-1 k-1, respectively, which represent a 32.77 % and 118.75 % increase compared to pure EP. Besides, the GTR is reduced to 122.57 cm3 m- 2 d-1 atm- 1, which is a 24.63 % decrease compared to pure EP.