Recent Progress on Two-Dimensional Carbon Materials for Emerging Post-Lithium (Na⁺, K⁺, Zn²⁺) Hybrid Supercapacitors

• Main Authors: Chao Han, Xinyi Wang, Jian Peng, Qingbing Xia, Shulei Chou, Gang Cheng, Zhenguo Huang, Weijie Li
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Polymers
• Subjects: 2D carbon materials; sodium-ion hybrid capacitor; potassium-ion hybrid capacitor; zinc-ion hybrid capacitor; challenges and prospects
• Online Access: https://www.mdpi.com/2073-4360/13/13/2137

The hybrid ion capacitor (HIC) is a hybrid electrochemical energy storage device that combines the intercalation mechanism of a lithium-ion battery anode with the double-layer mechanism of the cathode. Thus, an HIC combines the high energy density of batteries and the high power density of supercapacitors, thus bridging the gap between batteries and supercapacitors. Two-dimensional (2D) carbon materials (graphite, graphene, carbon nanosheets) are promising candidates for hybrid capacitors owing to their unique physical and chemical properties, including their enormous specific surface areas, abundance of active sites (surface and functional groups), and large interlayer spacing. So far, there has been no review focusing on the 2D carbon-based materials for the emerging post-lithium hybrid capacitors. This concept review considers the role of 2D carbon in hybrid capacitors and the recent progress in the application of 2D carbon materials for post-Li (Na⁺, K⁺, Zn²⁺) hybrid capacitors. Moreover, their challenges and trends in their future development are discussed.