An advanced sandwich-type architecture of MnCo2O4@N–C@MnO2 as an efficient electrode material for a high-energy density hybrid asymmetric solid-state supercapacitor. Issue 47 (22nd November 2018)

• Record Type: Journal Article
• Authors: Shrestha, Khem Raj; Kandula, Syam; Rajeshkhanna, G.; Srivastava, Manish; Kim, Nam Hoon; Lee, Joong Hee
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 47(2018)
• Page Start: 24509
• Page End: 24522
• Publication Date: 2018-11-22
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8ta08976k
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A thin layer of N–C sandwiched between an electroactive MnCo2 O4 core and MnO2 shell results in sophisticated, robust core@sandwich@shell as a highly efficient energy storage material. Abstract : The design and development of innovative heterostructures with multifunctional properties are technically very important for efficient practical energy storage and conversion applications. Herein, we report the synthesis of a nitrogen-doped carbon (N–C) layer sandwiched between MnCo2 O4 and MnO2 (MnCo2 O4 @N–C@MnO2 ) as a core@sandwich@shell type heterostructure on Ni foam. The thin layer of sandwiched N–C acts as a "superhighway" for good electron/ion transport and protects the MnCo2 O4 and MnO2 from destructive morphological changes during repeated charge–discharge processes. The MnCo2 O4 @N–C@MnO2 material is well characterized by standard techniques, and its energy storage performance is studied in a three-electrode system and solid-state asymmetric capacitor device. The resultant electrochemical performance is compared with those of MnCo2 O4 and MnCo2 O4 @N–C. The MnCo2 O4 @N–C@MnO2 electrode exhibits an excellent areal/gravimetric capacity of 0.75 mA h cm −2 /312 mA h g −1 at 3 mA cm −2 with ca. 89.6% capacitance retention after 10 000 cycles. A solid-state asymmetric supercapacitor device assembled with MnCo2 O4 @N–C@MnO2 as a cathode and nitrogen-doped graphene hydrogel as an anode exhibits a high energy density of 68.2 W h kg −1 at 749.2 W kg −1 power density without compromising long cycle life ( ca. 91.1% retention after 10 000 cycles). The highly efficient energy storage performance of this new class of heterostructures synthesized with earth-abundant materials enables commercial applications.