Abstract Mesoporous NiCo2O4 nanoneedle arrays on graphene film grown directly on a three-dimensional Ni foam have been fabricated by a facile hydrothermal method, accompanied by annealing under air atmosphere. The BET specific surface area of NiCo2O4@graphene film@Ni foam is as high as 47.65 m2 g−1. The porous composites served as a binder-free anode material for lithium-ion batteries display an excellent and stable electrochemical performance with high specific capacities of 1232 mAh g−1 at the current density of 500 mA g−1 over 100 cycles and 1493 mAh g−1 at the current density of 1500 mA g−1 after 230 cycles with Coulombic efficiency higher than 97%. Moreover, a fairly high rate capacity of 586 mAh g−1 retained even at a high current density of 8000 mA g−1. The outstanding electrochemical performance should be attributed to synergetic effect of NiCo2O4 nanoneedle arrays with mesoporous nature and high specific area as well as graphene substrate supporting, which can accommodate the volume variation during the electrochemical reactions and facilitate the ion and electron transmission.

中文翻译：

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在泡沫镍上生长的三维石墨烯薄膜上轻松合成介孔 NiCo 2 O 4 纳米针阵列，用于高性能无粘合剂锂离子电池负极

摘要 直接在三维泡沫镍上生长的石墨烯薄膜上的介孔 NiCo2O4 纳米针阵列已通过简便的水热法制备，并伴随在空气气氛中退火。NiCo2O4@石墨烯薄膜@泡沫镍的BET比表面积高达47.65 m2 g-1。多孔复合材料作为无粘合剂的锂离子电池负极材料显示出优异且稳定的电化学性能，在 500 mA g-1 的电流密度下，100 次循环和 1493 mAh g-1 的高比容量为 1232 mAh g-1 -1 在 1500 mA g-1 的电流密度下经过 230 次循环，库仑效率高于 97%。此外，即使在 8000 mA g-1 的高电流密度下，也保持了 586 mAh g-1 的相当高的倍率容量。