Confining MoS 2 nanodots in compact layered graphene blocks for high volumetric capacity, fast, and stable sodium storage

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-11, Vol.10 (42), p.22638-22644
• Main Authors: Liang, Shichuan, Zhang, Su, Liu, Zheng, Feng, Jing, Jiang, Yuting, Gao, Mingming, Geng, Di, Wei, Tong, Fan, Zhuangjun
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D2TA05935E

Sodium storage materials have gained increasing attention as next-generation power sources. However, realizing high volumetric capacity, high rate performance, and long-term stability remains challenging. Herein, we report a novel strategy for the confined growth of MoS 2 nanodots between densely nitrogen-doped graphene layers (DNG/MoS 2 ) assisted by electrostatic attraction between Mo 7 O 24 − anions and polyaniline coated graphene oxide nanosheets. The interlayer confined structure provides sufficient space for fast ion transport and accommodates the volume change of MoS 2 . The large contact area and strong interfacial Mo–N bonds between MoS 2 nanodots and nitrogen-doped graphene not only improve the electrical conductivity and charge-transfer kinetics, but also ensure good structural stability. Based on the above merits, DNG/MoS 2 delivers high gravimetric and volumetric capacities (514 mA h g −1 /1439 mA h cm −3 at 0.1 A g −1 ), remarkable rate performance (290 mA h g −1 /811 mA h cm −3 at 10 A g −1 ), and outstanding cycle stability (capacity retention of 82.4% over 2000 cycles at 1 A g −1 ). The assembled sodium ion capacitor exhibits the high energy densities of 129 W h kg −1 at 79 W kg −1 , as well as long-term cycle stability. Our work may provide new thoughts for designing high density advanced electrode materials.