A perpendicular micro-hole array for efficient ion transport in a thick, dense MoS2-based capacitive electrode

作者：Yang, Chuang; Wang, Peiyao; Xiong, Zhiyuan; Wu, Xin; Chen, Hui; Xiao, Jing; Zhou, Guangmin; Liang, Lixin; Hou, Guangjin; Li, Dan; Liu, Jefferson Zhe^*; Cheng, Hui-Ming^*; Qiu, Ling^*

来源：Energy Storage Materials, 2023, 60: 102843.

DOI：10.1016/j.ensm.2023.102843

• Volumetric capacitance
• Energy density
• Supercapacitor
• High thickness
• 2D materials

Two-dimensional (2D) nanosheets with a high electrochemical capacitance, density, and electrical conductivity are promising for assembling thick and dense films for supercapacitors with a high volumetric energy density. However, 2D nanosheet-based films with cascading nanochannel networks are not ideal for efficient ion transport due to the tortuous pathways. We used a micro-stamping method to create a perpendicular micro-hole array in a thick, dense MoS2-based electrode without lowering its density. Our nuclear magnetic resonance measurement and computational simulations reveal that the micro-hole array can serve as ion reservoirs and provide shortcuts in the cascading nanochannel network, greatly improving the ion accessibility to MoS2-based electrodes in both the adsorption and charging processes. A MoS2-based film electrode with 2-3 times the density of a conventional carbon electrode, shows almost thickness independent capacitance performance with a mass loading up to 18.6 mg cm-2. The electrode has a volumetric capacitance of 469.5 F cm-3 and the assembled device a volumetric energy density of 80.5 Wh L-1 in an ionic liquid electrolyte. This micro-stamping strategy is easy to scale up and may pave the way for the development of 2D materials-based compact energy storage systems.

• 单位
  中国科学院; 清华大学