Toward Enhanced Electrochemical Performance by Investigation of the Electrochemical Reconstruction Mechanism in Co₂V₂O₇ Hexagonal Nanosheets for Hybrid Supercapacitors

Abstract

As for hybrid supercapacitors, it is important to enhance the long cycling performance and high specific capacitance. In this paper, cobalt vanadate (Co 2 V 2 O 7 ) hexagonal nanosheets on nickel foam are manufactured by a facile hydrothermal method and then transformed into numerous smaller size interconnected hierarchical nanosheets without any shape change via electrochemical reconstruction. Benefiting from the favorable architecture of hierarchical nanosheets via electrochemical reconstruction, the Co 2 V 2 O 7 hexagonal nanosheet electrode exhibits a remarkable long cycling performance with 272% specific capacitance retention after 100,000 cycles at a current density of 5 A g −1 and then displays an increasing specific capacitance of 1834 F g −1 (tested at 1 A g −1 ). Furthermore, an aqueous hybrid supercapacitor device based on the Co 2 V 2 O 7 hexagonal nanosheet electrode exhibits a high energy density of 35.2 Wh kg −1 at a power density of 1.01 kW kg −1 and an excellent cyclic stability with 71.4% capacitance retention after 10,000 cycles at 5 A g −1 . These results offer a practicable pathway for enhancing the electrochemical properties of other metal oxides through electrochemical reconstruction.

Growth Dynamics‐Dependent Chemical Approach to Accomplish Nanostructured Cobalt Vanadium Oxide Thin Film Electrodes with Controlled Surface Area for High‐Performance Solid‐State Hybrid Supercapacitor Devices

“…Also, Hosseini et al [ 56 ] fabricated Co 3 V 2 O 8 ‐Ni 3 V 2 O 8 TLs@PCNFs//PCNFs reported SE of 59.7 Wh kg −1 at 1970 W kg −1 . Similar to the present work, the aqueous hybrid supercapacitor device based on Co 2 V 2 O 7 //rGO was fabricated by Wang et al, [ 11 ] which attained 35.2 Wh kg −1 SE at 101 W kg −1 SP. Moreover, the SHSD and ASHD devices manufactured in the present work demonstrated higher performance than the reported only similar device by Wang et al [ 11 ] in terms of SE and SP.…”

“…Similar to the present work, the aqueous hybrid supercapacitor device based on Co 2 V 2 O 7 //rGO was fabricated by Wang et al, [ 11 ] which attained 35.2 Wh kg −1 SE at 101 W kg −1 SP. Moreover, the SHSD and ASHD devices manufactured in the present work demonstrated higher performance than the reported only similar device by Wang et al [ 11 ] in terms of SE and SP. However, the reported energy densities for Co 3 V 2 O 8 //AC, [ 49 ] Co 3 V 2 O 8 //AC, [ 50 ] and Co 3 V 2 O 8 ‐Ni 3 V 2 O 8 ‐PCNFs//PCNFs [ 56 ] HASDs are slightly higher than the present work due to the use of Ni‐foam (NF) as a conductive substrate since Ni foam can add its self‐capacitance in the alkaline device.…”

“…[ 37 ] This work uses only SS as a conductive substrate, which avoids the redox reaction in the alkaline electrolyte; hence the obtained SE and SP originated from the CVO1:1 and rGO materials. Moreover, the position of the HASD device in the Ragone plot is higher than SHSD and reported hybrid devices in terms of SP, without scarifying much SE, [ 11,16,49–56 ] suggesting the suitability of CVO1:1 thin film electrode for next‐generation hybrid energy storage devices.…”

“…[7,8] Also, transition metal oxides (TMOs) are the favorite because of their special properties; multivalent states can provide ideal pseudocapacitance, proceeding electrons and ions intercalation into a metallic compound lattice, along with good intrinsic stability. [9][10][11] Several single TMOs like IrO 2 , Co 3 O 4 , V 2 O 5 , MnO 2 , RuO 2 , NiO, etc., and binary TMOs such as NiFe 2 O 4 , NiCo 2 O 4 , Co 3 V 2 O 8 , MnCo 2 O 4 , Ni 3 V 2 O 8 , etc. have been investigated as cathode material in HSCs.…”

NiCo2S4/MoS2 Nanocomposites for Long-Life High-Performance Hybrid Supercapacitors

“…We found that soaking the electrodes in the electrolyte for a long time (after activation) was quite favorable for enhanced cycling stability. Such drastic enhancement in electrochemical performance is associated with the electrochemical reconstruction of the electrode materials during cycling and soaking the electrode in electrolyte solution for a long time [ 32 ]. It is important to note that, after the soaking process, the capacitance retention increased to 207% at the 38,000th cycle, which can be associated with the re-activation of the electrode.…”