Improving Cycling Performance of Anode-Free Lithium Batteries by Pressure and Voltage Control

Abstract

Anode-free lithium batteries (AFLBs) have great potential to provide a higher energy density than most other batteries. However, the performance of AFLBs is very sensitive to pressure and other operating parameters. In this work, the operating voltage range and the internal pressures applied to AFLBs using a localized high-concentration electrolyte have been optimized for the coin cells widely used in the early stage research of AFLBs. With an optimized cycling protocol, a thin layer of uniform nucleation sites can be formed during the initial cycle, which will facilitate smooth Li deposition/stripping in the subsequent cycles of AFLBs. The solid− electrolyte interphase layer formed under optimized pressure and uniform pressure distribution exhibits good stability for long-term cycling. The internal pressure in the coin cells has been optimized to improve the cycling performance of AFLBs (Cu||NMC811) with 72% capacity retention in 100 cycles.

Anode-free lithium metal batteries: a promising flexible energy storage system

“…16), focusing on electrolytes and current collectors, while also providing insights into the challenges encountered during the manufacturing process of AFLMBs. 103–106…”

A high-current initiated formation strategy for improved cycling stability of anode-free lithium metal batteries

“…[11][12][13] However, it is challenging to improve the coulombic efficiency and lifespan of AFLMBs since there is no excess Li inventory to compensate for the loss of active Li caused by the Li dendritic growth, dead Li accumulation, side reactions between Li and the electrolyte, and the formation and breakage of the solid electrolyte interphase (SEI) during the Li plating/stripping process. [14][15][16] To overcome these issues, many strategies have been reported to enhance the reversibility of lithium plating/ stripping and the stability of the SEI, such as constructing articial protection layers on the anode current collector to guide uniform Li plating/stripping, [17][18][19] applying a high-concentration electrolyte to passivate the active Li metal surface, [20][21][22] introducing uorinated solvents into the electrolyte to foster a robust and LiF-enriched SEI, 23,24 adding cathode sacricial reagents to replenish the Li inventory in AFLMBs, 25,26 and optimizing the cycling conditions (charge/discharge rate, temperature, mechanical pressure, etc.). [27][28][29] These strategies are efficacious to suppress the Li dendrite growth, establish a robust SEI, or alleviate parasitic reactions between Li and the electrolyte.…”