High Performance Solid-state Battery with Integrated Cathode and Electrolyte

Lithium ion batteries (LIBs) are becoming the most popular energy storage systems in our society. However, frequently occurring accidents of electrical cars powered by LIBs have caused increased safety concern regarding LIBs. Solid-state lithium batteries (SSLBs) are believed to be the most promising next generation energy storage system due to their better in-built safety mechanisms than LIBs using flammable organic liquid electrolyte. However, constructing the ionic conducting path in SSLBs is challenging due to the slow ionic diffusion of Li ion in solid-state electrolyte, particularly in the case of solid-solid contact between the solid materials. In this paper, we demonstrate the construction of an integrated electrolyte and cathode for use in SSLBs. An integrated electrolyte and cathode membrane is obtained via simultaneous electrospinning and electrospraying of a polyacrylonitrile (PAN) electrolyte and a LiFePO4 (LFP) cathode material respectively, for the cathode layer, followed by the electrospinning of PAN to prepare the electrolyte layer. The resultant integrated PAN-LFP membrane is flexible. Scanning electron microscopy and energy dispersive X-ray spectroscopy measurement results show that the electrode and electrolyte are in close contact with each other. After the integrated PAN-LFP membrane is filled with a succinonitrile-bistrifluoromethanesulfonimide (SN-LiTFSI) salt mixture, it is paired with a lithium foil metal anode electrode, and the resultant solid-state Li vertical bar PAN-LFP cell exhibits limited polarization and outstanding interfacial stability during long term cycling. That is, the Li vertical bar PAN-LFP cell presents a specific capacity of 160.8 mAh.g(-1) at 0.1C, and 81% of the initial capacity is maintained after 500 cycles at 0.2C. The solid-state Li|PAN-LFP cell also exhibits excellent resilience in destructive tests such as cell bending and cutting.