锂硫电池电催化剂表面工程选择性硫转化,Carbon Energy

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锂硫电池电催化剂表面工程选择性硫转化
Carbon Energy ( IF 19.5 ) Pub Date : 2022-08-17 , DOI: 10.1002/cey2.249
Yuejin Zhu ₁ , Yinze Zuo ₁ , Xuechao Jiao ₁ , Revanasiddappa Manjunatha ₁ , Ejikeme Raphael Ezeigwe ₁ , Wei Yan _{1,

2} , Jiujun Zhang _{1,

2}

Affiliation

多相硫转化与均相和非均相电化学过程的缓慢动力学，导致可溶性多硫化物物质（PSs）的“穿梭效应”，是锂硫电池（LSBs）方面的挑战。在本文中，通过具有合理氧空位的表面工程设计了一种 Mn ₃ O _{4- x}催化剂，其对多相反应的活性远高于对均相反应的活性（即优先活性催化剂）。由于电子结构的合理设计，Mn ₃ O _{4− x}_{催化剂更倾向于加速Li 2} S ₄向Li ₂ S ₂的转化/Li ₂ S 并优化 Li ₂ S 沉积，减少 PS 的积累，从而抑制“穿梭效应”。密度泛函理论计算和原位 X 射线衍射测量均用于探索催化机理，并鉴定 MnS 和 Li y _Mn z _O 4− _x的反应中间体以进行基本理解。_{具有 Mn 3} O _{4− x}的电池在 2.5 C 下提供了 0.028% 的超低衰减率，超过 2000 个循环。即使在贫电解质中硫负载量为 4.93 和 7.10 mg cm ^-2（8.4 µL mg s ^-1)，电池仍显示出 7.3 mAh cm ^-2的初始面积容量。该研究可能为开发优先活性多相反应催化剂以抑制LSBs氧化还原过程中产生的可溶性PSs的“穿梭效应”提供一种新途径。

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Selective sulfur conversion with surface engineering of electrocatalysts in a lithium–sulfur battery

The sluggish kinetics of multiphase sulfur conversion with homogeneous and heterogeneous electrochemical processes, causing the “shuttle effect” of soluble polysulfide species (PSs), is the challenges in terms of lithium–sulfur batteries (LSBs). In this paper, a Mn₃O_4−x catalyst, which has much higher activity for heterogeneous reactions than for homogeneous reactions (namely, preferential-activity catalysts), is designed by surface engineering with rational oxygen vacancies. Due to the rational design of the electronic structure, the Mn₃O_4−x catalyst prefers to accelerate the conversion of Li₂S₄ into Li₂S₂/Li₂S and optimize Li₂S deposition, reducing the accumulation of PSs and thus suppressing the “shuttle effect.” Both density functional theory calculations and in situ X-ray diffraction measurements are used to probe the catalytic mechanism and identify the reaction intermediates of MnS and Li_yMn_zO_4−x for fundamental understanding. The cell with Mn₃O_4−x delivers an ultralow attenuation rate of 0.028% per cycle over 2000 cycles at 2.5 C. Even with sulfur loadings of 4.93 and 7.10 mg cm⁻² in a lean electrolyte (8.4 µL mg s⁻¹), the cell still shows an initial areal capacity of 7.3 mAh cm⁻². This study may provide a new way to develop preferential-activity heterogeneous-reaction catalysts to suppress the “shuttle effect” of the soluble PSs generated during the redox process of LSBs.

更新日期：2022-08-17

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