Graphene-Encapsulated CuP2: A Promising Anode Material with High Reversible Capacity and Superior Rate-Performance for Sodium-Ion Batteries
Graphene-Encapsulated CuP2: A Promising Anode Material with High Reversible Capacity and Superior Rate-Performance for Sodium-Ion Batteries
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石墨烯封装的 CuP2：一种有前途的钠离子电池负极材料，具有高可逆容量和优异的倍率性能
DOI：
10.1021/acs.nanolett.9b00342
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发表时间：
2019
期刊：
影响因子：
10.8
通讯作者：
Wu Minghong
中科院分区：
文献类型：
--
作者：
Zhang Yuanjun;Wang Guanyao;Wang Liang;Tang Liang;Zhu Ming;Wu Chao;Dou Shi-Xue;Wu Minghong
金属聚磷酸酯具有理论容量高、潜力大、资源丰富等优点，是理想的钠离子阳极。但它们大多存在不可逆性问题，表现为可逆容量低、库仑效率（CE）较差、速率能力低、循环稳定性差。在这项工作中，我们系统地比较了各种聚磷酸盐块体的电化学行为，发现与FeP2， CoP3和nip2块体相比，CuP2块体具有更高的初始可逆容量（416 mAh g-1 at 0.1 a g-1）和CE(74%)，这与CuP2独特的晶体结构有关。通过合理设计将cup2纳米颗粒封装在三维石墨烯网络中（CuP2@GNs），优化了cup2电极，从而获得了优异的电化学性能。在碳酸盐电解质中，CuP2@GNs电极可以分别在0.1,0.5,1,2和5 A g-1下提供高达804,736,685,621和508 mAh g-1的可逆容量，以及66%的首CE。可逆容量可达737 mAh g-1at 0.1 A g - 1，在乙醚电解质中首CE为83%。这些优异的性能表明CuP2@GNs是一种很有前途的钠离子电池负极材料。
Metal polyphosphides are regarded as the ideal anode candidates for sodium storage because of their high theoretical capacity, reasonable potential, and abundant resource alternative. However, most of them suffer from irreversibility problems, as reflected by their low reversible capacity, inferior Coulombic efficiency (CE), low rate capability, and poor cycling stability. In this work, we systematically compare the electrochemical behavior of a variety of polyphosphides bulks, discovering that the CuP2bulks have higher initial reversible capacity (416 mAh g–1at 0.1 A g–1) and CE (74%) compared to the FeP2, CoP3, and NiP2bulks, which is related to the unique crystal structure of CuP2. The CuP2electrode is optimized by the rational design of encapsulating CuP2nanoparticles into three-dimensional graphene networks (CuP2@GNs), leading to excellent electrochemical performance. In the carbonate electrolyte, the CuP2@GNs electrode can deliver the reversible capacities of up to 804, 736, 685, 621, and 508 mAh g–1at 0.1, 0.5, 1, 2, and 5 A g–1, respectively, along with a first CE of 66%. The reversible capacity can be up to 737 mAh g–1at 0.1 A g–1with a first CE of 83% in the ether electrolyte. These excellent performance demonstrates that CuP2@GNs could be a promising anode material for sodium-ion batteries.