Porous Cu Film Enables Thick Slurry-Cast Anodes with Enhanced Charge Transfer Efficiency for High-Performance Li-Ion Batteries.

Abstract

The ever-growing demand for energy in the consumer market has put higher requirements on the energy density of Li-ion batteries. Many researchers have strived to discover new electrode materials with higher capacity, while little attention has been focused on improving the cell structure. How to increase the thickness of conventional slurry-cast electrodes as well as decrease the charge transfer resistance by improving the electrode structure is an urgent problem for enhancing the energy density of Li-ion batteries. Here, a porous Cu film is developed to replace the conventional Cu foil current collector, and a thick graphite anode (300 μm) is engineered by two-side slurry casting. The anode delivers a maximum capacity of 18 mAh cm-2 or 301.3 mAh g-1 under a highly active mass loading of 60 mg cm-2, much higher than that fabricated on Cu foil. The assembled full cell with the graphite anode and the LiFePO4 cathode achieves high energy densities of 36.2 mWh cm-2 and 283.3 Wh kg-1. Systematic experimental and simulation investigations reveal the enhanced performance benefits from the facilitated charge transfer efficiency by the porous Cu current collector. This work provides a new strategy for engineering thick electrodes for high-energy Li-ion batteries by improving the conventional electrode structure.