Adsorption‐Catalysis Design in the Lithium‐Sulfur Battery

Abstract

Lithium‐sulfur (Li‐S) batteries are one of the most promising next‐generation energy‐storage systems. Nevertheless, the sluggish sulfur redox and shuttle effect in Li‐S batteries are the major obstacles to their commercial application. Previous investigations on adsorption for LiPSs have made great progress but cannot restrain the shuttle effect. Catalysts can enhance the reaction kinetics, and then alleviate the shuttle effect. The synergistic relationship between adsorption and catalysis has become the hotspot for research into suppressing the shuttle effect and improving battery performance. Herein, the adsorption‐catalysis synergy in Li‐S batteries is reviewed, the adsorption‐catalysis designs are divided into four categories: adsorption‐catalysis for LiPSs aggregation, polythionate or thiosulfate generation, and sulfur radical formation, as well as other adsorption‐catalysis. Then advanced strategies, future perspectives, and challenges are proposed to aim at long‐life and high‐efficiency Li‐S batteries.

Optimizing Redox Reactions in Aprotic Lithium–Sulfur Batteries

“…The redox reactions of Li–S battery in an aprotic electrolyte produce a series of soluble lithium polysulfides (LiPSs) (Li 2 S n , 2 < n ≤ 8) and insoluble Li 2 S 2 /Li 2 S, which give rise to a myriad of actual issues. [ 8,9 ] The most challenging one is the shuttle effect of soluble LiPSs driven by the concentration gradient, which causes the loss of electrochemically active S as well as the passivation of the Li anode, leading to severe capacity fading and poor cycle life. [ 10 ] Apart from the LiPSs shuttling, the electrochemical reactions of S also involve solid–liquid–solid phase transitions.…”

Free‐Standing Nanostructured Architecture as a Promising Platform for High‐Performance Lithium–Sulfur Batteries

“…Free‐standing architectures featuring an interwoven network possess large specific surface area and abundant porous space, which can localize the current density and accommodate volumetric variation during lithium plating/stripping when applied as the lithium matrices [3e,3f] . Thereby, the behaviors of lithium nucleation/growth in the free‐standing framework will be improved, enhancing the lifespan of the lithium anode.…”

“…Recently, various strategies have been developed to solve the aforementioned problems to improve the electrochemical performance of Li–S batteries, such as sulfur host design, separator modification, and lithium anode protection. [ 3 ] These strategies mainly depend on the design of novel electrode structures and interfacial layers to a great extent. Free‐standing architectures that are assembled by nanostructured building blocks often have tunable features with multiple functions, such as excellent mechanical properties, high electrical conductivity, and abundant porous structures.…”

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

“…[70] In general, O vacancy in sulfur hosts can form the abundant localized electron to improve the chemisorption of LiPSs but also reduce the energy barrier of the interfacial charge carrier to achieve the fast LiPSs catalytic conversion. [71] For instance, Mai et al have verified that the O vacancies in TiO 2 possess the high LiPSs adsorption ability, favorable catalytic ability, and superior ion/ electron conductivities based on the first-principle calculations and experiment operations. [72] By enhancing the binding energy of O vacancies-TiO 2 (OVs-TiO 2 ) to LiPSs, the O vacancies can increase the TiO polarity, improve the ionic conductivity, and facilitate the fast conversion of soluble long-chain LiPSs.…”

“…O vacancy is an important defect to adjust the structure and function of metal oxides in improving the electrochemical performance of Li−S batteries [70] . In general, O vacancy in sulfur hosts can form the abundant localized electron to improve the chemisorption of LiPSs but also reduce the energy barrier of the interfacial charge carrier to achieve the fast LiPSs catalytic conversion [71] . For instance, Mai et al.…”