A new paradigm for battery structural design towards interface-free, all-in-one cell configuration

Abstract

The commercial lithium-ion cell is based on layer-by-layer stacking of the cathode, porous separator, and anode laminates. The internal cathode/separator and anode/separator interfaces severely hamper Li-ion transport and displacement between the neighboring layers easily causes cell failure. Herein, we developed a novel interface-free cell configuration realized with a multifunctional polymer composite (LiPEAOB) which is used as both the electrode binder and the cell separator. The all-in-one cell configuration effectively eliminates the internal interfaces by holding all the cell components within the same LiPEAOB monolith. Meanwhile, the traditional porous separator is replaced by the nonporous and Li-conductive LiPEAOB membrane incorporated with nano Al₂O₃ filler. As such, we successfully overcome the two fundamental issues, namely (i) the high internal interfacial resistance and (ii) the cathode–anode cross-talk within the cell. The assembled LFP/graphite cell shows high rate capability, which can deliver a capacity of 104 mA h g⁻¹ at a 10C rate. We demonstrate a significantly improved cycle life of the proposed cell compared to the traditional counterpart at different charge/discharge rates. The new paradigm for battery architecture within a continuous functional polymer matrix is important to revolutionize the state-of-the-art assembly of lithium-ion batteries with extremely high rates and long cycle life.