具有碳纳米管基底的硫化交联聚苯乙烯刷的制备及其锂载体性能  

Fabrication of vulcanized cross-linked polystyrene grafted on carbon nanotubes for use as an advanced lithium host

作　　者：柯贤澜 卢宇恒 吴金伦 吴丁财 KE Xian-lan;LU Yu-heng;WU Jin-lun;WU Ding-cai(PCFM Lab,School of Chemistry,Sun Yat-sen University,Guangzhou 510006,China;Guangdong Cardiovascular Institute,Guangdong Provincial People’s Hospital,Guangdong Academy of Medical Sciences,Guangzhou 510080,China)

机构地区：[1]中山大学化学学院,聚合物复合材料及功能材料教育部重点实验室,广东广州510006 [2]广东省人民医院,广东省医学科学院,广东省心血管病研究所,广东广州510080

出　　处：《新型炭材料（中英文）》2023年第4期743-753,共11页New Carbon Materials

基　　金：国家重点研发计划(2021YFF0500600);国家自然科学基金(51925308).

摘　　要：不可控的锂枝晶生长、严重的体积膨胀以及脆弱的固态电解质中间相(SEI)严重制约了锂金属电池(LMBs)的实际应用。在本研究中,我们成功设计合成了一类具有碳纳米管基底的硫化超交联聚苯乙烯刷(CNT-g-sxPS),并将其用作新型的三维锂金属载体。CNT-g-sxPS的层次化大孔、中孔和微孔能够促进锂离子的传输,缓解锂负极的体积变化,提供高比表面积以降低局部电流密度,从而实现快速且均匀的锂沉积/剥离。同时,孔骨架表面均匀分布的含硫基团可以与锂原位反应生成含Li2S的SEI,有利于构筑稳定的负极/电解液界面。此外,碳纳米管基底还能提供快速的电子传输路径。因此,利用CNT-g-sxPS负载的锂金属负极(CNT-g-sxPS@Cu/Li)组装的Li|Li对称电池在1 mA cm^(-2)、1 mAh cm^(-2)下可稳定循环超过500 h。当与磷酸铁锂正极(LFP)匹配时,利用CNT-g-sxPS@Cu/Li负极组装的全电池在1 C下循环600圈后仍然具有101 mAh g^(-1)的放电比容量,容量保持率为77%。We report the fabrication of vulcanized cross-linked polystyrene grafted on carbon nanotubes(CNTs)for use as an ad-vanced three-dimensional Li host.First,polystyrene was grafted from Br-modified CNTs to form brush-like structure by surface-ini-tiated atom-transfer radical polymerization.Polystyrene grafted on carbon nanotubes was then cross-linked using a Friedel-Crafts re-action and finally vulcanized with sulfur.Vulcanized cross-linked polystyrene grafted on carbon nanotubes was used as a support for the Li metal,and its macro-,meso-and microporous structure increased Li ion transport,buffered the volume changes of the Li an-ode,and provided a high specific surface area to reduce local current density,which assisted rapid and uniform Li plating/stripping.At the same time,the homogenously distributed sulfur in the support reacted with Li to produce a Li2S-containing SEI layer,while the CNTs provided conductive pathways for the rapid transmission of electrons.As a result,a Li|Li symmetric cell using this anode material and a Cu current collector had a stable cycling performance of more than 500 h at a current density of 1 mA cm^(-2).When LiFePO4 was used as the cathode,a full cell had a high discharge capacity of 101 mAh g^(-1) with a capacity retention of 77%after 600 cycles at 1 C.

关 键 词：硫化超交联聚苯乙烯刷 碳纳米管基底 三维锂载体 含有Li2S的SEI 锂金属电池 

分 类 号：TQ127.11[化学工程—无机化工]