石墨烯//CNT涂层的的集流器，用于提高固态锂离子电池的倍率性能

1成果简介

锂离子电池（LIBs）凭借其高能量密度、长循环寿命和多功能性，已成为消费电子产品、电动汽车和固定式能源存储系统中不可或缺的电源。然而，基于液体电解质的传统LIBs存在显著的安全风险，包括电解质泄漏、易燃性和在高电压下电化学稳定性有限等问题。作为更安全的替代方案，固态聚合物电解质——尤其是基于聚乙二醇的电解质——正受到越来越多的关注。为了提升其实际应用性，研究人员探索了阴极电解质配置。然而，这些配置被报道会增加内部电阻，阻碍实际应用。

因此，本文，韩国庆尚大学Soobeom Lee等研究人员在《Journal of Alloys and Compounds》期刊发表名为“Interface-Engineered Current Collectors for Improved Rate Performance in Solid-State Lithium-Ion Batteries”的论文，研究提出了一种替代策略，即在铝电流收集器上依次沉积石墨烯和碳纳米管（G//CNT）涂层。该方法在无需额外无机组分的情况下，同时提升了界面稳定性和电子导电性。值得注意的是，G//CNT涂层集流体展现出优化的电化学性能，初始比容量达200.1 mAh g−1 （0.2 C）并在2 C下保持45.08mAh g−1 的容量。因此，本研究为提升下一代固态锂离子电池的实际性能提供了简单且可扩展的解决方案。

2图文导读

图1. SEM images of NMP-based electrode: (a) low-magnification, (b) high-magnification, (c) cross-sectional view with elemental mapping profiles of Ni, Co, Mn, and C. SEM images of the catholyte-based electrode: (d) low-magnification, (e) high-magnification, (f) cross-sectional view with elemental mapping profiles of Ni, Co, Mn, and C. (g) Schematic of a solid-state LIB incorporating a catholyte layer. (h) XRD patterns of NMC in the NMP-based and catholyte-based electrodes.

图2. Electrochemical characterization of the NMP-based and catholyte-based electrodes: (a) Nyquist plots of the NMC electrodes, illustrating the impedance characteristics of the NMP-based and catholyte-based samples. (b) Relationship between real impedance (Zreal) and ω−1/2 for the two electrode types. (c) CV curves of the two electrodes. (d) Rate performance at various C-rates.

图3. Schematic illustration of the catholyte electrode incorporating a functional current collector consisting of sequential graphene and CNT layers coated on Al foil. This layered structure is designed to enhance interfacial adhesion and mechanical stability at the catholyte interface in solid-state batteries.

图4. Schematic illustrations of current collectors: (a) bare Al, (b) graphene-coated Al (G/Al), (c) CNT-coated Al (CNT/Al), (d) graphene–CNT-composite-coated Al (G@CNT/Al), and (e) sequentially layered graphene/CNT-coated Al (G//CNT/Al). (f)–(j) Corresponding low-magnification SEM images and (k)–(o) corresponding high-magnification SEM images (p) TGA results of graphene and CNT powders. (q) XRD patterns of graphene, CNT samples. (r) Raman spectra of graphene and CNT samples.

图5. Contact angle measurements of (a) bare Al, (b) G/Al, (c) CNT/Al, (d) G@CNT/Al, and (e) G//CNT/Al surfaces. (f) Comparison of the contact angle values of each configuration.

图6. Electrochemical performance of bare Al, G/Al, CNT/Al, G@CNT/Al, and G//CNT/Al electrodes. (a) Nyquist plots obtained from EIS measurements. (b) Comparison of charge-transfer resistance (Rct) values. (c) Z′ vs. ω−1/2 plots. (d) CV curves. (e) Rate performance at various C-rates. (f) Comparison of rate performance between the G//CNT/Al electrode and previously reported NMC-based ASSBs.

图7. XPS spectra of bare Al and G//CNT/Al electrodes after cycling: F 1 s spectra of (a) bare Al and (b) G//CNT/Al. (c) Relative composition of the F 1 s spectra. Al 2p spectra of (d) bare Al and (e) G//CNT/Al. (f) Relative composition of the Al 2p spectra.

3小结

本研究提出了一种可扩展的界面工程策略，通过依次在铝电流收集器上涂覆石墨烯和碳纳米管层（G//CNT/Al），以提升固态锂离子电池（LIB）的电化学性能和稳定性。G//CNT双层结构设计同时提高了电导率并抑制了界面副反应。电化学分析表明，G//CNT/Al-E样品展现出最低的电荷转移电阻（109.5 Ω）， 锂离子扩散系数最高（σw = 17.2），以及比容量最高（0.2 C时为197.0 mAh g^(−1)，2 C时为45.1 mAh g^(−1)），在所有测试配置中表现最佳。XPS分析进一步证实了铝-氟化物形成被抑制，且集流体表面金属铝的保留率提高至27%，表明界面具有长期稳定性。这些改进源于碳纳米管和石墨烯的互补作用：碳纳米管增强了界面接触和机械强度，而石墨烯作为化学稳定的屏障防止了铝的腐蚀。G//CNT配置还展现出与固态阴极电解质的优异润湿性，其接触角（33°）在所有样品中最低。综合而言，这些结果表明所提出的G//CNT界面层解决了聚合物基锂离子电池的关键局限性，包括高界面电阻和循环过程中的退化。总体而言，本研究为开发适用于电动汽车和电网规模能源存储系统的高性能、安全且可扩展的固态锂离子电池提供了可行路径。

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来源：材料分析与应用