MXene-based O/Se-rich bimetallic nanocomposites for high performance solid-state symmetric supercapacitors

• Published in: Journal of solid state chemistry 2022-02, Vol.306, p.122727, Article 122727
• Main Authors: Karkuzhali, Rajendran, Manoj, Shanmugasundaram, Shanmugapriya, Karnan, Narendra Kumar, Alam Venugopal, Gopu, Gopalakrishnan, Muniyappan, N., Jeon, Byong-Hun, Muthu Prabhu, Subbaiah
• Format: Article
• Language: English
• Subjects: Bimetallic O/Se; Energy storage; MXene; Supercapacitor; Symmetric device
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2021.122727

Herein, we developed a novel and high-performance supercapacitor material for by incorporating an electron-rich oxalate-modified cobalt and nickel selenide (CoNi(Ox)Se) on the surface of MXene. The formation of O/Se-loaded CoNi on the MX, affording enhanced electron transport between the electrodes. A high pseudocapacitive charge storage behavior of the CoNi(Ox)Se@MX composite is confirmed, exhibiting a specific capacitance of 1782 ​F ​g−1at 5 ​mV ​s−1in a KOH (1 ​M) electrolyte solution. This capacitance value is considerably higher than that of Co-based electrodes reported in the literature. Furthermore, electrochemical cyclic measurements indicated that material stability is retained after 1000 cycles at 5 ​A ​g −1. Notably, when set up as a solid symmetric capacitor, the synthesized electrodes exhibit a high energy density of 131.9 ​Wh kg−1at a power density of 7.2 ​kW ​kg−1, along with flexibility. The material possesses an excellent capacitance retention (95%) after 5000 cycles without loss of any metals/Se. The results indicate that the MX-based composite promoted rapid electrolyte diffusion, fast kinetics in terms of electron-transport, and high charge/discharge rates. Thus, CoNi(Ox)Se@MX structures may have the potential for the development of novel energy storage systems suitable for portable, miniaturized, and wearable power devices. [Display omitted] •O/Se-loaded CoNi on MXene is developed for high-performance supercapacitor•It delivers specific capacitance of 1782 ​F ​g−1 with excellent stability over 1000 cycles•The material shows high energy density (131.9 ​Wh kg −1) and power density (7.2 ​kW ​kg−1)•The symmetric supercapacitor displays zero-loss even after 5000 cycles.