Roll-to-roll fabrication of ultrathin graphite-like amorphous carbon film modified Al foil current collectors for high-voltage LiNi0.5Mn1.5O4 lithium-ion batteries

Conventional aluminum (Al) foil current collectors suffer from severe pitting corrosion at high operating voltage and local corrosion during cycling, which has become a critical bottleneck for the development of next-generation high-voltage lithium-ion batteries (LIBs). Herein, we develop an ultrathin graphite-like amorphous carbon film modified Al (GAC@Al) foil current collector via a scalable roll-to-roll multi-arc ion plating process for high-voltage LiNi0.5Mn1.5O4 (LNMO) LIBs. The as-prepared GAC film features a unique graphite-like local ordering within an amorphous matrix, achieving an exceptional combination of ultrathin thickness (~30 nm), strong adhesion to Al substrate (peel strength of 379.69 N m-1), and high electrical conductivity (sheet resistance of 0.123 mΩ sq-1). This enables effective electrochemical anti-corrosion protection of the current collector, leading to significantly enhanced cycling stability and rate capability. High-voltage LNMO cells based on GAC@Al foil current collector present superior electrochemical performance in comparison with those using bare Al and commercial coating carbon Al foil. The GAC@Al-based LNMO cells deliver superior cycling stability with 83.1% capacity retention after 1000 cycles at 1C as well as 82.7% capacity retention after 800 cycles at 5C, along with improved rate performance. The roll-to-roll multi-arc ion plating process employed in the fabrication of GAC@Al current collector is readily scalable, environmentally friendly and compatible with industrial LIB production. This study offers a new strategy for protecting Al current collectors and advances the practical application of next-generation 5 V LIBs.