Cost-effective natural graphite reengineering technology for lithium ion batteries
Cost-effective natural graphite reengineering technology for lithium ion batteries
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DOI：
10.1016/j.cclet.2023.108330
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发表时间：
2023-11-09
影响因子：
9.1
通讯作者：
Liu, Jianhong
中科院分区：
文献类型：
--
作者：
Liu, Pei;Wang, Hongbin;Liu, Jianhong
天然石墨产生的石墨尾矿通常被视为垃圾埋在地下，这会造成一定的资源浪费。为了探索天然石墨尾矿（NGT）的综合利用，采用液体聚丙烯腈（WPAN）对NGT碎片进行改性，并将其聚集在一起，形成低比表面积、高振实密度的二次石墨颗粒。此外，改性后的NGT的电化学性能也明显优于未改性的NGT。当在与NMC 532阴极耦合的全电池中测试时，该材料在4.25 V和4.45 V的截止电压下实现了高倍率容量和循环稳定性，其在1C倍率（4.25 V）下500次循环后保持84.32%的容量保持率，高于原始材料（73.65%）。增强的性能可以归因于使用WPAN在石墨尾矿上产生独特的碳层以重建表面和修复缺陷，并且还使二次石墨颗粒具有各向同性结构，这可以有助于削弱Li +扩散路径的各向异性并形成均匀的，在初级NGT碎片的表面上形成完整且稳定的固体电解质界面（SEI），以促进Li +的快速扩散并抑制充电和放电时的锂金属枝晶。(c)2023由Elsevier B.V.代表中国化学会和中国医学科学院药物研究所出版。
Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground, which would result in a certain waste of resources. Here, in order to explore the utilization of natural graphite tailings (NGT), a liquid-polyacrylonitrile (LPAN) is used to modify the NGT fragments and aggregate them together to form secondary graphite particles with low surface area and high tap density. Moreover, the modified NGT show much better electrochemical performances than those of original one. When tested in full cells coupled with NMC532 cathode, the material achieves a high rate capability and cycle stability at the cutoff voltage of 4.25 V as well as 4.45 V, which maintains 84.32% capacity retention after 500 cycles at 1 C rate (4.25 V), higher than that of the pristine one (73.65%). The enhanced performances can be attributed to the use of LPAN to create a unique carbon layer upon graphite tailings to reconstruct surface and repair defects, and also to granulate an isotropic structure of secondary graphite particles, which can help to weaken the anisotropy of Li + diffusion pathway and form a uniform, complete and stable solid-electrolyte-interface (SEI) on the surface of primary NGT fragments to promote a fast Li + diffusion and suppress lithium metal dendrites upon charge and discharge. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.