High-performance flexible hybrid-supercapacitor enabled by pairing binder-free ultrathin Ni–Co–O nanosheets and metal-organic framework derived N-doped carbon nanosheets. (20th July 2020)

• Record Type: Journal Article
• Authors: Javed, Muhammad Sufyan; Aslam, Muhammad Kashif; Asim, Sumreen; Batool, Saima; Idrees, Muhammad; Hussain, Shahid; Shah, Syed Shoaib Ahmad; Saleem, Muhammad; Mai, Wenjie; Hu, Chenguo
• Is Part Of: Electrochimica acta. Volume 349(2020)
• Publication Date: 2020-07-20
• Subjects: Bimetallic oxides -- Electrode -- Hybrid supercapacitor -- Flexible -- High energy density; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.136384
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: High-rate electrochemical hybrid supercapacitors (HSCs) have attracted great scientific attention due to the expectation of the battery-level energy density and super long life as electrochemical double-layer capacitors. But in reality, the rational design of HSCs with a balanced capacity of positive and negative electrodes with high-rate capability is still a great challenge. Herein, a unique strategy is applied by pairing the binder-free NiCo2 O4 ultrathin nanosheets supported on carbon fiber paper (Ni–Co–O@CFP) as cathode and metal-organic-framework (MOF) derived nanoporous nitrogen-doped carbon nanosheets (NPC) as an anode to fabricate the hybrid supercapacitor (NCO||NPC-HSC). The specific capacitance of the Ni–Co–O@CFP electrode reaches 2038 F g −1 (339 mAh g −1 ) at 1.5 A g −1 with capacitance retention of 93.65% after 5000 charge-discharge cycles at a high current density of 20 A g −1 . The as-fabricated NCO||NPC-HSC exhibited excellent electrochemical properties in PVA/KOH hydrogel electrolyte with highly flexible characteristics. The NCO||NPC-HSC can work under the extended potential window of 0.0–1.6 V and reach at a high specific capacitance of 201 F g −1 at 0.55 A g −1, providing ultra-high energy density of 69 Wh kg −1 at a power density of 840 W/kg, which is substantially higher than values reported for symmetric and asymmetric supercapacitors based on the NiCo2 O4 till date. Moreover, the NCO||NPC-HSC demonstrated the negligible change in performance while bent at different states. Overall, our NCO||NPC-HSC exhibits exceptionally good cycling performance over 20, 000 cycles (>90% capacitance retention). Interestingly, three NCO||NPC-HSC devices connected in series can power 16 green color light-emitting-diodes (LEDs, 2 V) for more than 2 min, demonstrating its fusibility as a practical energy storage device. Graphical abstract: The proposed design of hybrid supercapacitor based on binder-free Ni–Co–O nanosheets and nanoporous carbon (Ni–Co–O||NPC-HSC) exhibits record high energy storage performance. The Ni–Co–O||NPC-HSC delivered high energy density of 69 Wh kg −1 at 840 W/kg with high flexibility. Image 1