Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (5): 444-450.DOI: 10.6023/A20010011 Previous Articles    



汤功奥, 毛鲲, 张静, 吕品, 程雪怡, 吴强, 杨立军, 王喜章, 胡征   

  1. 南京大学化学化工学院 介观化学教育部重点实验室 南京 210023
  • 投稿日期:2020-01-12 发布日期:2020-05-15
  • 通讯作者: 吴强, 王喜章;
  • 基金资助:

Hierarchical Nitrogen-doped Carbon Nanocages as High-rate Long-life Cathode Material for Rechargeable Magnesium Batteries

Tang Gong-ao, Mao Kun, Zhang Jing, Lyu Pin, Cheng Xueyi, Wu Qiang, Yang Lijun, Wang Xizhang, Hu Zheng   

  1. Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
  • Received:2020-01-12 Published:2020-05-15
  • Supported by:
    Project supported by the jointly financial support from the National Key Research and Development Program of China (2018YFA0209100, 2017YFA0206500) and the National Natural Science Foundation of China (21773111, 21972061, 21832003, 21573107, 51571110).

Rechargeable magnesium batteries (rMBs) are promising next-generation secondary batteries owing to the low-cost, high safety and dendrite-free property of Mg metal. The key of rMBs technology is to develop high-performance cathode materials. Usually, the intercalation-type cathodes such as Mo6S8, MoS2 and Ti3C2Tx suffer from the inferior rate performance owing to the sluggish Mg2+ ions solid-diffusion kinetics, and the conversion-type cathodes such as S and CuS are beset with the poor cycling stability owing to the pulverization and loss of active species. Recently, sp2 carbon materials exhibited considerable magnesium storage performance through an interfacial charge storage/release. Ideal carbon-based cathodes for rMBs should possess the features of high specific surface area and abundant active sites for magnesium storage, high conductivity and porous structure for facilitating charge transfer, as well as high mechanical stability. Herein, we employed the hierarchical nitrogen-doped carbon nanocages (hNCNC) featuring large surface area, abundant surface defects, coexisting micro-meso-macropores and high conductivity as the rMBs cathode for the first time, which exhibited high discharge capacity of 71 mAh·g-1 at 100 mA·g-1, excellent rate performance (60 mAh·g-1 at 2000 mA·g-1) and ultra-high cycling stability (83% capacity retention after 1000 cycles at 1000 mA·g-1). The capacitive magnesium storage mechanism is predominant in the charging-discharging process. Theoretical studies reveal that magnesium ions are adsorbed on the carbon, pyridinic-nitrogen or pyrrolic-nitrogen atoms at the edge of micropores. The excellent magnesium storage performance of hNCNC is attributed to the following reasons:(i) the hNCNC with large surface area (1590 m2·g-1), abundant micropore defects and high content of pyridinic and pyrrolic nitrogen (4.49 at.%) provides sufficient active sites for magnesium storage, resulting in the high discharge capacity; (ii) the coexisting micro-meso-macropores structure, good conductivity and improved wettability via N-doping facilitate the charge transfer kinetics, and decrease the equivalent series resistance of rMBs, thereby leading to the improved rate capability; (iii) the robust scaffold of hNCNC and the capacitive-dominated magnesium storage mechanism ensure the high cycling stability. This study demonstrates the high-rate and durable performance of hNCNC in rMBs, and suggests a promising strategy to improve the rMBs performance by increasing edges and suitable dopants of nanocarbons.

Key words: rechargeable magnesium battery, cathode material, nitrogen-doped carbon nanocage, capacitive-dominated mechanism, high-rate long-life performance