A carbon fiber lamina electrode based on macroporous epoxy with vertical ion channels for structural battery composites

Structural battery (SB) composites based on carbon fibers (CFs) are promising multifunctional composite materials to simultaneously realize load-bearing and electrical energy storage. Conventional structural battery electrolytes (SBEs) have bicontinuous phase microstructure characteristics, which makes a further considerable improvement in both mechanical and electrochemical performance of structural batteries rather challenging. Herein, a novel SBE with vertical ion channels in the form of patterned macropores was developed by photolithography based on the UV-initiated cationic polymerization, which was subsequently used in the fabrication of the CF half-cell lamina. The mechanical and electrochemical properties were characterized for both SBE and SB half-cells. The Young's modulus and ionic conductivity of the porous epoxy post-filled with liquid electrolyte were 1.2 GPa and 3.7 mS/cm, respectively, which exceeded the state-of-art multifunctional performances of bicontinuous SBEs. The specific capacity of the SB half-cell could reach 222 ± 10 mAh/g (2nd) at 0.17C, while the tensile modulus of the CF half-cell lamina was 66 ± 4 GPa (Vf = 22.5 %). This work could provide new insights into a microstructural design for structural batteries towards high multifunctional performances.