Multifunctional analysis of novel aluminum-ion structural battery composites with optimization in cathode material

Structural battery composites are promising structural energy storage solution receiving growing attention. Graphite intercalation compounds rechargeable battery utilizing aluminum chloride ions is considered for application in structural battery composites for resource abundancy and high safety. However, the severe volume expansion of traditional graphite cathodes during cycling significantly poses threats to long-term performance of structural battery composites. In this work, we develop aluminum-ion structural battery composites using vacuum infusion process and compare the electrochemical and mechanical performance of structural battery composites incorporating few-layer graphene and natural graphite cathode materials respectively. The structural battery composites utilize carbon fibers coated with the active materials as both electrode and reinforcing material. It is demonstrated that employing few-layer graphene instead of conventional natural graphite as the active material effectively alleviates the volume expansion issues during cycling, improving the flexural strength attenuation rate of the structural battery composites significantly from 91 % to 23.3 % after 30 cycles. Additionally, structural battery composites utilizing few-layer graphene coating exhibit impressive mechanical properties with a tensile strength of 299.4 MPa and tensile modulus of 22.12 GPa, while maintaining energy density of 22.58 Wh/kg based on the weight of active materials (8.3 Wh/kg for whole cell).