Ultrathin rGO coatings regulate interfacial evolution of aluminum current collectors in high-voltage lithium-ion batteries

A drop-coating and VC-immersion reduction method for preparing ultrathin rGO coating on Al foil. • rGO-coated Al foil current collectors enhance the electrochemical performance of LIBs. • Thickness–defect synergy influences the performance enhancement of rGO coating on CCs. Carbon-coated aluminum has emerged as a promising current collector (CC) for lithium batteries, offering significant advantages such as mitigating aluminum foil corrosion, reducing interfacial electron transfer resistance, and enhancing long-term cycling stability and rate performance. In this work, an ultrathin reduced graphene oxide (rGO) coating was fabricated on aluminum foil through a facile binder-free drop-coating and Vitamin C-immersion reduction method. By tuning the GO loading amount, a series of rGO-coated CCs with different coating thicknesses was obtained and evaluated in LiMn 2 O 4 (LMO) batteries under 4.5 V. The results show that electrochemical performance is not determined by coating thickness alone, but by the synergistic effects of coating thickness and defect density. Among samples, the CCs with rGO coating of less than 5 nm thickness exhibit the best rate performance and durability, retaining 85.2% capacity after 500 cycles at 1C (148 mAh·g −1 ), far surpassing pure Al CCs (73.2%). Post-cycling analyses indicate that the ultrathin rGO coating effectively stabilizes the interfacial environment and mitigates corrosion-related surface degradation during cycling. These findings not only advance our understanding of the role of carbon coatings in mitigating degradation mechanisms but also pave the way for the development of more efficient and durable energy storage systems. Download: Download high-res image (155KB) Download: Download full-size image