Transition Metal Dichalcogenides as Effective Catalysts for High-Rate Lithium–Sulfur Batteries

Abstract

In today's renaissance of high-energy-density secondary batteries, lithium−sulfur (Li−S) batteries represent one of the most promising candidates for the next generation of renewable energy storage systems due to sulfur's high theoretical specific capacity of 1675 mA h g −1 and high earth abundance. However, despite decades of study, the issues associated with capacity fade via the polysulfide shuttle and sluggish kinetics remain. Through a rigorous and detailed electrochemical study of lithium polysulfides via rotating disk electrode (RDE) voltammetry, we have investigated the kinetics of the redox reactions and explored candidate catalysts to potentially overcome/mitigate the polysulfide shuttle effect. From these RDE studies, supported by comprehensive electronic structure calculations of conversion-type surface reactions, we determined that WSe 2 can effectively catalyze the polysulfide redox reaction, though further studies are necessary to improve the overall Li−S battery performance.

A polyaniline-coated Ni–Co Prussian blue analogue nanocube-modified separator for high-performance lithium–sulfur batteries

“…The Li + ion diffusion coefficient ( D Li ) can be evaluated through the linear relationship between the peak current ( I p ) and the square root of the scan rate ( v 0.5 ) using the Randles–Sevcik equation. 33 The equation is represented as: I p = (2.69 × 10 5 ) n 1.5 AD Li 0.5 C Li v 0.5 where n , A , and C Li represent the charge transfer number, electrode surface area, and lithium ion concentration in the electrolyte. Based on this equation, the points of I p and v 0.5 were fitted for the oxidation process (Peak A) and two reduction processes (Peak B and Peak C), as shown in Fig.…”

“…The Li + ion diffusion coefficient (D Li ) can be evaluated through the linear relationship between the peak current (I p ) and the square root of the scan rate (v 0.5 ) using the Randles-Sevcik equation. 33 The equation is represented as:…”

High Entropy Sulfide Nanoparticles as Lithium Polysulfide Redox Catalysts

“…Theoretically, K-L analysis is valid only for simple one electron transfer processes. In practice, so long as the kinetic values are not taken as the actual, specific rate, but are instead used only to compare the rates of the same reaction under different conditions, it is valuable for analysis of catalysts. − K-L plots for the oxidation showed noncoupled electron transfer kinetics over the entire kinetic potential regime (Figure c). However, for the reduction (Figure d), a change in the electrochemical behavior emerges at high rotation rates (1500 and 1800 rpm), which we attribute to a short-lived intermediate that does not have enough time to react when the rotation rate is too high. ,, …”

Dynamic evolution of electrocatalytic materials for Li–S batteries

“…[21][22][23][24][25] Finally, the sluggish conversion kinetics from liquid Li 2 S 4 to solid Li 2 S and Li 2 S decomposition bring about low utilization of active materials, [26][27][28][29] which leads to a capacity decline, especially under high sulfur loading and lean electrolyte conditions. [30][31][32][33] Over the past few decades, there has been a full swing of conceptualizing various strategies, comprising physical restriction, [34][35][36][37][38] chemical adsorption, [39][40][41] and catalytic conversion, 26,42 to solve the foregoing challenges, with special attention paid to the notorious shuttle effect and sluggish redox reaction kinetics. 43,44 In the early stages, nanostructured porous carbons introduced into host materials serve as reaction microchambers to physically confine LiPSs.…”

“…Over the past few decades, there has been a full swing of conceptualizing various strategies, comprising physical restriction, 34–38 chemical adsorption, 39–41 and catalytic conversion, 26,42 to solve the foregoing challenges, with special attention paid to the notorious shuttle effect and sluggish redox reaction kinetics. 43,44 In the early stages, nanostructured porous carbons introduced into host materials serve as reaction microchambers to physically confine LiPSs.…”