Enhanced Performance of Flexible Quasi-Solid-State Lithium Batteries with High-Loading Cathode Enabled by Laser Drilling

Abstract

Gel electrolyte composite with high areal capacity cathode effectively improves battery energy density and safety. Still, the insufficient interface contact between electrolyte and electrode limits the capacity release inside the thick cathode. Here, we rationally design a self-supporting cathode and use the in-situ polymerization method to integrate the gel electrolyte with the cathode. This cathode can effectively reduce the content of inactive electrode components. Meanwhile, the design of the regularly-arranged pore structure of the cathode introduced by laser texturing facilitates the penetration of the prepolymer solution and enables outstanding lithium-ion transport. Notably, the high-loading (15.1 mg cm -2 ) quasi-solid LiFePO 4 /Li half-cell exhibits good electrochemical performance (131.3 mAh g -1 after 100 cycles at room temperature). Moreover, when the loading of active materials increases to 30 mg cm -2 , the LiFePO 4 / Li 4 Ti 5 O 12 full-cell can still have a relatively high discharge capacity (105.9 mAh g -1 after 400 cycles at 0.2 C at room temperature). It is worth noting that the quasi-solid pouch cell prepared by in-situ polymerization has a certain flexibility, indicating that this strategy has application potential in flexible electronic devices.

Keywords: Li-ion battery, high areal capacity cathode, Cellulose nanofibers, multi-walled carbon nanotubes, laser drilling technology, flexibility