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Facet-Tailoring Five-Coordinated Ti Sites and Structure-Optimizing Electron Transfer in A Bifunctional Cathode with Titanium Nitride Nanowire Array to Boost the Performance of Li2S6-based Lithium-Sulfur Batteries
Energy Storage Materials ( IF 18.9 ) Pub Date : 2019-12-20 , DOI: 10.1016/j.ensm.2019.12.032
Chenyang Zha , Xiaorong Zhu , Jun Deng , Yuan Zhou , Yongshen Li , Junmei Chen , Pan Ding , Yongpan Hu , Yafei Li , Houyang Chen

Lithium-sulfur (Li-S) batteries are a promising candidate for renewable next-generation energy storage technologies with low cost and high performance. However, their performances are limited by the “shuttle effect” of polysulfides. Herein, a bifunctional hierarchical structure of three-dimensional titanium nitride (TiN) nanowire array (NA) with exposed (200) facets is prepared as an efficient polysulfide-anchoring center. Benefitting from this chemical tailoring strategy, the TiN-NA-based electrode not only provides stable well-dispersed and highly ordered nanowires to accelerate the efficient transition of redox charge carriers and to further promote the redox kinetics of polysulfide conversion, but also suggests five-coordinated Ti sites on (200) facets to enhance the adsorption ability for polysulfides. With the advances of the newly developed materials, liquid Li2S6-based TiN NA electrodes (area: 2 cm2) offer large initial capacities of 1214 and 1150 mAh/g, and hold 856 and 520 mAh/g with 1.0 and 3.0 mg/cm2 sulfur loadings at 1.6 mA/cm2 after 500 cycles, respectively. Specifically, the Galvanostatic intermittent titration technique suggests a strong adsorption capacity of TiN-NA-based electrodes in artificial strong polysulfide diffusion conditions during discontinuous charging and discharging processes. This work offers a novel concept of tailoring uncoordinated Ti sites and optimizing electron transfer in polysulfide redox reactions to effectively tackle the “shuttle effect”.



中文翻译:

氮化钛纳米线阵列双功能阴极上的五面体裁切配位五点钛和优化结构的电子转移,以提高基于Li 2 S 6的锂硫电池的性能

锂硫(Li-S)电池是低成本,高性能的可再生下一代储能技术的有希望的候选者。但是,它们的性能受到多硫化物的“穿梭效应”的限制。在此,制备具有暴露的(200)小平面的三维氮化钛(TiN)纳米线阵列(NA)的双功能分层结构,作为有效的多硫化物固定中心。得益于这种化学剪裁策略,基于TiN-NA的电极不仅可提供稳定的分散良好且高度有序的纳米线,以加速氧化还原电荷载流子的有效转变并进一步促进多硫化物转化的氧化还原动力学,而且还提出了五种协调(200)刻面上的Ti位,以增强多硫化物的吸附能力。基于2 S 6的TiN NA电极(面积:2 cm 2)提供1214和1150 mAh / g的大初始容量,并以1.6 mA / cm的1.0和3.0 mg / cm 2的硫负载保持856和520 mAh / g的初始容量2 500次循环后,分别。具体而言,恒电流间歇滴定技术表明,在不连续的充放电过程中,在人工强多硫化物扩散条件下,TiN-NA基电极具有很强的吸附能力。这项工作提供了一种新颖的概念,可以裁剪未配位的Ti位点并优化多硫化物氧化还原反应中的电子转移,从而有效解决“穿梭效应”。

更新日期:2019-12-21
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