Designing Advanced Liquid Electrolytes for Alkali Metal Batteries: Principles, Progress, and Perspectives

Abstract

The ever‐growing pursuit of high energy density batteries has triggered extensive efforts toward developing alkali metal (Li, Na, and K) battery (AMB) technologies owing to high theoretical capacities and low redox potentials of metallic anodes. Typically, for new battery systems, the electrolyte design is critical for realizing the battery electrochemistry of AMBs. Conventional electrolytes in alkali ion batteries are generally unsuitable for sustaining the stability owing to the hyper‐reactivity and dendritic growth of alkali metals. In this review, we begin with the fundamentals of AMB electrolytes. Recent advancements in concentrated and fluorinated electrolytes, as well as functional electrolyte additives for boosting the stability of Li metal batteries, are summarized and discussed with a special focus on structure–composition–performance relationships. We then delve into the electrolyte formulations for Na‐ and K metal batteries, including those in which Na/K do not adhere to the Li‐inherited paradigms. Finally, the challenges and the future research needs in advanced electrolytes for AMB are highlighted. This comprehensive review sheds light on the principles for the rational design of promising electrolytes and offers new inspirations for developing stable AMBs with high performance.

Engineering current collectors for advanced alkali metal anodes: A review and perspective

“…Alkali metals have attracted extensive research attention as promising alternative anodes for the next‐generation battery technologies. They own ultrahigh theoretical capacities of 3860, 1166, and 685 mAh g −1 and low redox potentials of −3.040, −2.714, and − 2.930 V vs. standard hydrogen electrode (SHE) for Li, Na, and K, respectively 4 . Despite the inferior electrochemical potential and specific capacity of Na and K to those of Li, the natural abundance, wide distribution, and low cost of Na and K resources make them great promising anodes for large‐scale energy storage 5,6 …”

Sodium–gallium alloy layer for fast and reversible sodium deposition

“…[8][9][10][11][12] As an important branch, lithium metal batteries (LMBs), including lithium-sulfide and lithium-oxygen batteries, can greatly boost the energy density of lithium-based batteries. [13][14][15][16][17][18] Unfortunately, lithium metal faces the bottleneck of the low reserves. Comparatively, with similar chemical properties, sodium metal batteries can be considered a wonderful alternative to LMBs as Na metal possesses low redox potential (-2.71 V vs. standard hydrogen electrode), high theoretical specific capacity (1166 mAh g −1 ), and abundant resources.…”

“…Over the past decades, lithium‐based batteries cut a brilliant figure emerging as a powerful life in the field of energy storage all over the world 8–12 . As an important branch, lithium metal batteries (LMBs), including lithium‐sulfide and lithium‐oxygen batteries, can greatly boost the energy density of lithium‐based batteries 13–18 . Unfortunately, lithium metal faces the bottleneck of the low reserves.…”

Uniform Lithium Deposition Induced by ZnFx(OH)y for High-Performance Sulfurized Polyacrylonitrile-Based Lithium-Sulfur Batteries

“…Therefore, low Coulombic efficiency (CE) and safety issues hinder the practical applications of LMBs. To address the above issues, researchers have proposed various strategies, such as the structural design of LMAs [ 11 , 12 ], current collector modifications [ 13 , 14 ], utilization of artificial SEIs [ 15 , 16 ] and electrolytes [ 17 , 18 ].…”