Study on modification of polymer 3D array structure on aluminum foil current collector surfaces in lithium-ion battery

Aluminum (Al) foil is a generally used cathode current collector in lithium-ion batteries (LIBs). During operation, insufficient interfacial compatibility between the current collector and the active material can lead to the delamination of the active material. Additionally, the surface of the Al foil is susceptible to corrosion by the electrolyte, which further compromises the structural integrity of the current collector. Addressing the challenges of existing modification techniques, which often rely on complex processes and struggle to simultaneously achieve interfacial modification and corrosion protection, this study employs a simple electrochemical polymerization strategy. It constructs a polyaniline (PANI) layer with a 3D array structure on the Al foil surface, integrating the dual functions of enhanced interfacial adhesion and electrolyte protection. The LFP battery assembled with the modified current collector (LFP-PANI/Al) has exhibited 6.2% increase in discharge-specific capacity at 1 C rate compared to the LFP battery assembled with bare Al foil current collector (LFP-Bare Al). Meanwhile, after 1000 cycles at 2 C rate, the discharge-specific capacity has reached 63.9 mAh g −1 , while the LFP-Bare Al group has achieved only 32.6 mAh g −1 . This work offers new insights for future modifications of current collectors to improve the long-term cycling stability of LIBs.