Anionic oxygen vacancies in Nb2O5-x/carbon hybrid host endow rapid catalytic behaviors for high-performance high areal loading lithium sulfur pouch cell
Anionic oxygen vacancies in Nb2O5-x/carbon hybrid host endow rapid catalytic behaviors for high-performance high areal loading lithium sulfur pouch cell
复制标题
Nb2O5-x/碳杂化主体中的阴离子氧空位赋予高性能高面积负载锂硫软包电池的快速催化行为
DOI：
10.1016/j.cej.2020.128172
复制
发表时间：
2021-05-12
影响因子：
15.1
通讯作者：
Lin, Hongzhen
中科院分区：
文献类型：
--
作者：
Cheng, Shuang;Wang, Jian;Lin, Hongzhen
锂离子在硫电池中的传输过程中存在着严重的穿梭效应和缓慢的电化学转化动力学过程，阻碍了锂/硫电池的发展。本工作在高导电性的分级多孔纳米碳上制备了氧化铌纳米颗粒中的阴离子氧空位，作为硫锚和锂离子加速器。光学显色和电化学测试表明，缺氧型电催化剂对多硫化物具有更强的相互作用能力，并赋予其优越的推动离子动力学和促进Li 2S沉淀的上级催化能力。理论模拟还表明，当多硫化物与AOV-Nb_2 O_5-x催化剂相互作用时，形成Nb-S键。结果表明，所制备的硫阴极具有较高的初始容量（1489 mAh·g ~（-1）），理论利用率为89%，在1C下循环600次后仍具有较长的寿命。提高电流速率至5C时，倍率容量为899 mAh·g（-1），显示出快速的转化动力学。令人印象深刻的是，即使用贫电解质将面积负载增加到4.2mg cm（-2），袋式电池仍然可以在0.343mA cm（-2）下表现出3.54mA h cm（-2）的初始面积容量，并且稳定数十次循环，为快速充电电池提供了希望。
The development of lithium/sulfur batteries has been hindered by notorious shuttling effect and sluggish electrochemical conversion kinetics owing to high barrier of lithium ion transport behaviors. In this work, anionic oxygen vacancies in niobium oxide nanoparticle is fabricated on a high-conductive hierarchical porous nano-carbon as a sulfur anchor and lithium ion accelerator. As evidenced by optical coloration and electrochemical measurements, the oxygen-deficient electrocatalyst shows much stronger interaction ability to polysulfides and endows superior catalytic ability of propelling ion kinetics and facilitating the precipitation of Li2S. Theoretical simulations have also revealed that Nb-S bonds are formed when polysulfides interacts with AOV-Nb2O5-x catalyst. Consequently, the as-prepared sulfur cathode exhibits a high initial capacity of 1489 mA h g(-1), corresponding to the theoretical utilization of 89%, and a long life for 600 cycles at 1 C. Enhancing current rate to 5 C, a rate capacity of 899 mA h g(-1) is obtained, demonstrating rapid conversion kinetics. Impressively, even increasing the areal loading to 4.2 mg cm(-2) with the lean electrolyte, the pouch cell can still exhibit the initial areal capacity of 3.54 mA h cm(-2) at 0.343 mA cm(-2) and stabilize for several tens of cycles, providing the promise for fast-charge batteries.