Study on the Commercial Metalized Plastic Current Collector PET-Cu and PP-Cu Toward High-Energy Lithium-Ion Battery

Commercial metalized plastic current collector (MPCC) is receiving widespread attention from the business and academic communities, due to its properties of excellent electrical conductivity and low mass density. However, the application of MPCC on the side of copper is rarely studied. Herein, sandwich-like polyethylene terephthalate-based (PET) and polypropylene-based (PP) copper (Cu) current collectors via magnetron sputtering and electroplating are fabricated. Most importantly, the electrical performance, mechanical safety quality, and revealed the corresponding failure mechanism for the MPCC cells are first systematically evaluated. First, during the 45 °C electrical cycling tests, PET-Cu CC (82.67%) and PP-Cu CC (82.32%) cells both have comparable capacity retention with the traditional Cu CC (Tra-Cu CC) cell (84.55%) after 500 cycles. The slight reduction in the cycling performance is induced by the crack of the Cu layer around the embedded SiO₂ particle for PET-Cu CC cell and the detachment of Cu layer for PP-Cu CC cell. Second, during the nail-penetration test, MPCC cells maintain no fire and explosion for more than 5 min, since the heat-shrinkable function of polymeric film can interrupt the continuous Joule heat released by internal short-circuit. This work provides important guidance for the large-scale application of MPCC in the field of lithium-ion batteries.