Interface-engineered metalized plastic current collectors for fast-charging lithium-ion batteries with high safety and stability

Adopting the metalized plastic current collector (MPCC) enhances the safety and specific energy density of lithium-ion batteries (LIBs) but sacrifices the rate capability. The reduced rate capability is customarily ascribed to the lower electronic conductivity of MPCC as compared with the metal ones (e.g., Al and Cu) due to the less metal usage. Here, we demonstrate that the interfacial contact between the current collector (CC) and the active-material layer, rather than the electronic conductivity of CC, accounts for the rate performance of the cells. By introducing a thin carbon coating (∼300 nm) onto the surface of MPCC (e.g., 1 μm thick aluminum deposited on both sides of 10 μm polyethylene terephthalate (PET) film, Al-PET), we reduced the contact resistance between MPCC and cathode materials. Using the carbon-coated Al-PET (C@Al-PET) as CC, the 6.0-Ah graphite/LiCoO 2 pouch cell delivers significantly improved fast-charge capability and cycling stability, which are identified as the homogenized potential distribution and electrode utilization with multiphysical field simulations. Most importantly, the cell with C@Al-PET CC could still pass the harsh impact test, promising its applications in high-rate LIBs with superior safety. • Contact resistance between the active materials and current collector accounts for the rate performance of the cells. • A thin carbon coating on metalized plastic current collector (MPCC) reduces the contact resistance. • Fast-charging lithium-ion batteries with long life and superb safety are achieved with carbon-coated MPCC.