Direct electrophoretic deposition of an ultra-strong separator on an anode in a surfactant-free colloidal system for lithium ion batteries

A hierarchically laminated nanostructured PVdF-HFP membrane is deposited directly on a carbon anode through efficient, scalable electrophoretic deposition (EPD) in a surfactant-free colloidal system. Lithium ion batteries based on the separator-anode configuration have a well-structured microscopic interface with uniform, reinforced separator/electrode contact. The resulting separator enables a high ionic conductivity of 8.1 x 10(-4) S cm(-1), and exhibits a low thermal shrinkage of 3% after annealing at 160 degrees C for 5 h, a high isotropic mechanical strength (approximate to 33 MPa) and an ultra-high ductility (approximate to 450%). The battery with the separator-anode configuration delivers a discharge capacity of 370 mA h g(-1) (99.5% of the theoretical capacity) at 0.1C, an excellent capacity retention of approximate to 100% after 300 cycles, and a pronounced rate capability of 270 mA h g(-1) at 1C. This work opens up the opportunity to realize both reliable and high-capacity material platforms for next-generation lithium ion batteries.