Tong Zhongqiu, Yang Rui, Wu Shilin, Shen Dong, Jiao Tianpeng, Zhang Kaili, Zhang Wenjun, Lee Chun-Sing
Department of Chemistry, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Department of Materials Science and Engineering, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Small. 2019 Jul;15(28):e1901272. doi: 10.1002/smll.201901272. Epub 2019 Jun 4.
Nanoscale surface-engineering plays an important role in improving the performance of battery electrodes. Nb O is one typical model anode material with promising high-rate lithium storage. However, its modest reaction kinetics and low electrical conductivity obstruct the efficient storage of larger ions of sodium or potassium. In this work, partially surface-amorphized and defect-rich black niobium oxide@graphene (black Nb O @rGO) nanosheets are designed to overcome the above Na/K storage problems. The black Nb O @rGO nanosheets electrodes deliver a high-rate Na and K storage capacity (123 and 73 mAh g , respectively at 3 A g ) with long-term cycling stability. Besides, both Na-ion and K-ion full batteries based on black Nb O @rGO nanosheets anodes and vanadate-based cathodes (Na V O and K V O for Na-ion and K-ion full batteries, respectively) demonstrate promising rate and cycling performance. Notably, the K-ion full battery delivers higher energy and power densities (172 Wh Kg and 430 W Kg ), comparable to those reported in state-of-the-art K-ion full batteries, accompanying with a capacity retention of ≈81.3% over 270 cycles. This result on Na-/K-ion batteries may pave the way to next-generation post-lithium batteries.
纳米级表面工程在提高电池电极性能方面发挥着重要作用。氧化铌是一种典型的具有高倍率锂存储潜力的负极材料。然而，其适度的反应动力学和低电导率阻碍了钠或钾等较大离子的高效存储。在这项工作中，设计了部分表面非晶化且富含缺陷的黑色氧化铌@石墨烯（黑色Nb₂O₅@rGO）纳米片，以克服上述钠/钾存储问题。黑色Nb₂O₅@rGO纳米片电极在3 A g⁻¹ 时分别具有高倍率的钠和钾存储容量（分别为123和73 mAh g⁻¹），并具有长期循环稳定性。此外，基于黑色Nb₂O₅@rGO纳米片负极和钒酸盐基正极（钠离子全电池和钾离子全电池分别为Na₃V₂O₅和K₃V₂O₅）的钠离子和钾离子全电池均展现出良好的倍率和循环性能。值得注意的是，钾离子全电池具有更高的能量和功率密度（分别为172 Wh Kg⁻¹ 和430 W Kg⁻¹），与最先进的钾离子全电池报道相当，在270次循环中容量保持率约为81.3%。钠离子/钾离子电池的这一结果可能为下一代锂后电池铺平道路。
