Reasonable design of high-rate, long-life anode materials is the key to manufacturing advanced lithium-ion batteries. Herein, we synthesized the heterometallic (Ni, Co) 4,4′-biphenyldicarboxylic metal organic framework (NiCo-MOF-1) and heterometallic (Ni, Co) 2,2′-bipyridine-5,5′-dicarboxylic metal organic framework (NiCo-MOF-2) by solvothermal method, and explored the applications as anode materials for lithium-ion batteries in depth. It was demonstrated that the initial discharge/charge specific capacities of NiCo-MOF-1 and NiCo-MOF-2 reached 2.04/1.12 and 1.99/1.11 mAh cm⁻² at a current density of 0.1 mA cm⁻² and the voltage window of 0.01 ∼ 3.0 V, respectively. Similarly, NiCo-MOF-2 could maintain a specific discharge/charge capacity of 0.65/0.64 mAh cm⁻² after 150 cycles, which was higher than that of NiCo-MOF-1 (0.45/0.43 mAh cm⁻²). In addition, NiCo-MOF-2 delivers outstanding rate performance (0.29/0.29 mAh cm⁻² at 1.0 mA cm⁻²), which came down to the strong conjugated carboxylate π–π interaction and the synergistic effect of nickel and cobalt bimetals. Through the kinetic analysis, the pseudocapacitance contribution was as high as 61.7% at 0.5 mV s⁻¹. Ex-situ XPS verified the coordination mechanism of Li⁺ and COO⁻ rings with benzene ring in NiCo-MOF-2 thus achieving high lithium storage capacity.

中文翻译：

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异金属镍钴有机骨架的设计与合成作为高性能锂存储负极材料

合理设计高倍率、长寿命的正极材料是制造先进锂离子电池的关键。在此，我们合成了异金属（Ni，Co）4,4'-联苯二羧酸金属有机骨架（NiCo-MOF-1）和异金属（Ni，Co）2,2'-联吡啶-5,5'-二羧酸金属有机骨架(NiCo-MOF-2)采用溶剂热法制备，并深入探索其作为锂离子电池负极材料的应用。结果表明，NiCo-MOF-1 和 NiCo-MOF-2 的初始放电/充电比容量在 0.1 mA cm ^-2的电流密度和电压窗口为2.04/1.12 和 1.99/1.11 mAh cm ^-2时达到分别为 0.01 ∼ 3.0 V。同样，NiCo-MOF-2 可以保持 0.65/0.64 mAh cm ^{-2的比放电/充电容量}150 次循环后，高于 NiCo-MOF-1 (0.45/0.43 mAh cm ^-2 )。此外，NiCo-MOF-2 具有出色的倍率性能（在 1.0 mA cm ^{-2 时为 0.29/0.29 mAh cm -2 ）}，这归结为强共轭羧酸盐π–π镍钴双金属的相互作用和协同效应。^{通过动力学分析，赝电容贡献在 0.5 mV s -1}时高达 61.7% 。异地XPS 验证了 NiCo-MOF-2 中 Li ⁺和 COO ^-环与苯环的配位机制，从而实现高储锂容量。