Catalyzing polysulfide redox conversion for promoting the electrochemical performance of lithium-sulfur batteries by CoFe alloy

NbN nanodot decorated N-doped graphene as a multifunctional interlayer for high-performance lithium–sulfur batteries

“…In contrast, a similar symmetric battery without Li 2 S 6 addition in the electrolyte shows approximately linear-shaped CV curves for NbN and NbN@NG, which implies that Li 2 S 6 is the radically electrochemically active species in Li-S systems. 17,29 The interfacial reaction kinetics and electrocatalytic activity are assessed by using the exchange-current density (i 0 ). According to the Tafel plots in the overpotential interval from À150 to 150 mV (Fig.…”

“…Notwithstanding the shuttle effect of LiPSs which can be partly buffered, the limited active spots and internal spaces will bring about the accumulation of LiPSs, which will give rise to the structural collapse of the host materials. 17 In this regard, introducing the functional interlayer between the cathode and separator has been proved to avoid this situation, further regulating volume change and improving active species retention within the cathode. [18][19][20][21] As is generally known, the concept of a modied interlayer, which acts as a secondary current collector and conductive layer, was rst proposed by Manthiram's group in 2012.…”

Electrocatalyst Modulation toward Bidirectional Sulfur Redox in Li–S Batteries: From Strategic Probing to Mechanistic Understanding

“…(d-f) Reproduced with permission. [113] Copyright 2021, Elsevier. g) Schematic diagram showing the reduced reaction polarization with nano-HEA.…”

“…For instance, Hu et al collected ex situ X-ray adsorption spectra at different discharge/charge states during electrochemical reaction process, which is beneficial to probing the dynamic changes of valence and chemical environment of initial CoFe alloy. [113] To begin with, the peak of Co K-edge X-ray adsorption near edge structure (XANES) spectra shifts toward higher energies during SRR process (Figure 4d), manifesting the increased Co valence arising from the intense combination between CoFe alloy and electronegative PSs. Note that the peak shifts back to the initial state after SER process, indicating the superior structural stability of bimetallic CoFe alloy during electrocatalytic reaction process.…”

“…d) XANES, e) FT-EXAFS, and f) WT-EXAFS spectra of Co K-edge at different states during the first charge/discharge cycle. (d-f) Reproduced with permission [113]. Copyright 2021, Elsevier.…”