Perfluorosulfonic Acid Membranes as Gel-Polymer Electrolytes for Lithium Metal Batteries

Abstract

Gel-polymer electrolytes based on perfluorinated cation-exchange membranes are promising electrolytes for lithium metal batteries due to the strength and chemical stability of the fluorinated matrix and high values of ionic conductivity and cation transference numbers, which contribute to the suppression of dendrite formation. The present work compares the main characteristics of polymer electrolytes based on short-side-chain membranes Aquivion-87 and Aquivion-98 with different numbers of functional groups and content of polar aprotic solvents (mixtures of ethylene carbonate−propylene carbonate and ethylene carbonate−N,N-dimethylacetamide), i.e., ionic conductivity, transference numbers, and stability against lithium metal. Electrochemical characteristics of the electrolytes in Li|Li and LiFePO 4 |Li cells show good compatibility and functionality with the Li metal anode, forming a stable Li/electrolyte boundary, and LFP| Aquivion-87-EC-DMA|Li cell shows discharge capacity values of ∼142 mAh/g at 0.1 C and 136 mAh/g at 1 C and room temperature, with a 98.8% capacity retention after 70 cycles at 0.1 C. These data indicate their promising application as polymer electrolytes in lithium metal batteries.

Novel Strategy for Designing rGO@LLZTO@Li Composite Lithium Powder Anodes with a Dual Conducting Ion-Electron Channel for High-Energy-Density Lithium Metal Batteries

“…With the rapid development of electric vehicles, consumer electronics, and energy storage systems, the demand for high-energy-density rechargeable lithium batteries are significantly increasing. − Lithium metal batteries (LMBs) are promising rechargeable lithium batteries owing to the Li metal anode (LMA) having an ultrahigh theoretical specific capacity (3860 mA h g –1 ) and lowest redox potential (−3.04 V vs the standard hydrogen electrode). − However, the traditional plain Li foil anode can cause several safety issues of Li dendrite growth by the lithium nonuniform deposition, which hinder the practical application of LMBs. − Moreover, the uneven Li deposition brings low Coulombic efficiency (CE) and poor cycle performance, resulting in internal short circuits and even fire or explosion. − It is therefore very meaningful research to develop the novel structure of the anode to achieve uniform Li-ion (Li + ) flux on the surface of LMA.…”