3D独立式纳米管状石墨烯薄膜，用于无粘结剂锂离子电池阳极

摘要：金属碳化物被认为是极具吸引力的锂离子电池（LIB）负极材料。然而，它们的潜在实际应用仍需要纳米结构的优化，以进一步提高锂存储容量，尤其是在大电流密度下。本文，哈尔滨工业大学（深圳）曹博轩副教授、邱华军副教授、上海交通大学 Kolan Madhav Redd

1成果简介

金属碳化物被认为是极具吸引力的锂离子电池（LIB）负极材料。然而，它们的潜在实际应用仍需要纳米结构的优化，以进一步提高锂存储容量，尤其是在大电流密度下。本文，哈尔滨工业大学（深圳）曹博轩副教授、邱华军副教授、上海交通大学 Kolan Madhav Reddy副教授等在《Small methods》期刊发表名为“Nanoporous Graphene with Encapsulated Multicomponent Carbide as High-Performance Binder-Free Lithium-Ion Battery Anodes”的论文，研究设计了一种纳米多孔结构多金属碳化物，并将其封装在三维独立纳米管状石墨烯薄膜（MnNiCoFe-MoC@NG）中。这种具有高比表面积的独立式复合阳极不仅能提供更多的活性锂储存位点，还能有效防止传统粉末状电极中活性材料的团聚或脱落。此外，这种独立式设计在用作锂离子电池阳极时不需要额外的粘合剂、导电剂甚至集流器。

因此，MnNiCoFe-MoC@NG阳极在2Ag-1条件下显示出 1129.2mAh g+-1的高比容量，并且在5Ag-1条件下循环2900次后仍能保持 512.9mAh g-1的稳定容量，高于大多数已报道的基于 MoxC 的阳极。此外，该阳极在0 ℃和-20 ℃两种温度下均表现出卓越的低温性能，尤其是在大电流密度下。这些特性使得这种独立阳极在快速充电和低温应用中大有可为。

2图文导读

图1、a) Scheme showing the fabrication process of the MnNiCoFe-MoC@NG. b) XRD patterns of the samples at different stages. c) SEM image of the sample after the CVD treatment. SEM images d,e) and photographs f) of the MnNiCoFe-MoC@NG. Inset in (f) shows the flexibility of the composite.

图2、a–c) HAADF-STEM images of MnNiCoFe-MoC@NG with different magnifications. HAADF-STEM images of d) a single solid MoC particle and e) the nanoporous MoC. f) High-resolution TEM images of the MoC and coated graphene (inset). g) STEM-EDS elemental mapping images of the MnNiCoFe-MoC@NG.

图3、Electrochemical performance. a) Rate and cycle performances of MnNiCoFe-MoC@NG, MnNiCoFe-Mo2C@NG, NG-800 and NG-950. b) Cycling performance at 0.1 A g−1. c) Specific capacity and coulombic efficiency of MnNiCoFe-MoC@NG at 0.1 A g−1. d) Cycling performance of these anodes at 1 A g−1. e) Specific capacity and Coulombic efficiency of MnNiCoFe-MoC@NG at 1 A g−1 and f) the corresponding charge–discharge profiles. Specific capacity and Coulombic efficiency of MnNiCoFe-MoC@NG at 2 g) and 5 h) A g−1. (i) Comparing the cyclic performance and capacity with other MoxC-based composites anode materials (Table S4, Supporting Information).

图4、a) CV curves of MnNiCoFe-MoC@NG at 0.1 mV s−1 in the initial three cycles and b) the corresponding charge-discharge profiles at 0.1 A g−1. c) Ex situ XRD patterns of MnNiCoFe-MoC@NG acquired during discharge/charge at 0.1 A g−1 with the corresponding voltage profile on the left.

图5、a) CV curves and b) log|| against log. c) The percentages of pseudocapacitive contribution at different scan rates. d) The detailed pseudocapacitive contribution at 0.5 mV s−1 for MnNiCoFe-MoC@NG. e) Voltage response over time during a single current pulse. f) Li diffusion coefficients of MnNiCoFe-MoC@NG. g) Ex situ Nyquist plots of MnNiCoFe-MoC@NG acquired during 0.1 A g+−1 discharge/charge and h) the Rct, Rs values. i) Nyquist plots of the electrode at different cycle stages.

图6、a) Rate performances of MnNiCoFe-MoC@NG at different temperatures. Initial charge-discharge profiles of MnNiCoFe-MoC@NG from 0.1 to 5.0 A g−1 at 0 °C b) and −20 °C (c). d–f) Cycle performances at 0 °C and −20 °C.

3小结

利用脱合金纳米多孔锰镍钴铁钼合金作为模板，结合 CVD 和进一步的化学蚀刻，制备出了具有封装多组分碳化物的独立N掺杂纳米多孔石墨烯纳米管状网络。高导电性纳米管状石墨烯网络与基于MoC的纳米多组分碳化物相结合，提供了大量的锂存储点，即使在5Ag-1 的条件下，也能提供512.9mAh g+-1 的高比容量。此外，无粘合剂和封装设计有效解决了传统电极中活性材料脱落的问题，从而大大提高了循环稳定性和速率性能，并降低了成本。这些优点使得所开发的独立电极成为基于 MoxC 的最佳复合阳极之一。

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