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具有高度增强的离子传输性能以实现快速充电锂离子电池的氧掺杂WS与碳层的原子尺度层状结构

Atomic-Scale Laminated Structure of O-Doped WS and Carbon Layers with Highly Enhanced Ion Transfer for Fast-Charging Lithium-Ion Batteries.

作者信息

Li Zhenwei, Yuan Fu, Han Meisheng, Yu Jie

机构信息

Advanced Fibers Group, Songshan Lake Materials Laboratory Dongguan, Guangdong, 523808, China.

Shenzhen Engineering Lab for Supercapacitor Materials, Shenzhen Key Laboratory for Advanced Materials, School of Material Science and Engineering, Harbin Institute of Technology, Shenzhen, University Town, Shenzhen, 518055, China.

出版信息

Small. 2022 Jul;18(27):e2202495. doi: 10.1002/smll.202202495. Epub 2022 Jun 7.

Abstract

WS anode materials show huge potential for fast-charging lithium-ion batteries (LIBs) due to the naturally good 2D diffusion pathways but suffer from large Li diffusion barrier energy and poor intrinsic electrical conductivity. Here, a defect-rich atomic-scale laminated structure of WS and C (D-WS -C) with O doping and enlarged interlayer distance from 0.62 to 1.06 nm of WS is first fabricated, which is assembled into micron-sized spheres to prepare WS /C composite microspheres. D-WS -C with maximized molecular layer contact area between WS and carbon and large interlayer spacing greatly enhances the electrical conductivity of WS and reduces Li-ion diffusion energy barrier, confirmed by density functional theory calculations. Besides, the unique D-WS -C enables the formation of vast superfine W nanoparticles (1-2 nm) during the conversation reaction, resulting in the construction of a space charge zone on W surface. Based on these characteristics of D-WS -C, the prepared WS /C composite microspheres show superior fast-charging capability with a high capacity of 647.8 mAh g at 20 C in half cells. For full cells, a high-energy density of 100.9 Wh kg is achieved at a charge time of only 8.5 min at 5 C, representing the best fast-charging performances in WS -based anode materials to date.

摘要

由于具有天然良好的二维扩散路径,WS负极材料在快速充电锂离子电池(LIBs)方面显示出巨大潜力,但存在较大的锂扩散势垒能量和较差的本征电导率。在此,首次制备了具有O掺杂且WS层间距从0.62 nm扩大到1.06 nm的富含缺陷的WS和C原子尺度层状结构(D-WS -C),将其组装成微米级球体以制备WS /C复合微球。密度泛函理论计算证实,WS与碳之间分子层接触面积最大化且层间距大的D-WS -C极大地提高了WS的电导率并降低了锂离子扩散能垒。此外,独特的D-WS -C在转化反应过程中能够形成大量超细微的W纳米颗粒(1-2 nm),从而在W表面构建空间电荷区。基于D-WS -C的这些特性,所制备的WS /C复合微球在半电池中于20 C时表现出优异的快速充电能力,容量高达647.8 mAh g。对于全电池,在5 C下仅8.5分钟的充电时间内即可实现100.9 Wh kg的高能量密度,代表了迄今为止基于WS的负极材料中最佳的快速充电性能。

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