A study of Co‐Mn phosphate supported with graphene foam as promising electrode materials for future electrochemical capacitors

Abstract

Mn and Co are known for their redox storage mechanism depending on the kinetics of their ions, which is required to boost capacity values of the material electrodes for energy storage applications. However, to the best of our knowledge, Co-Mn phosphate material-based electrochemical capacitors have been rarely investigated. In this work, CoMn(PO 4 ) 2 synergized with graphene foam (GF) was synthesized following an easy, direct and low-temperature hydrothermal method. The study investigated the synergy between Co, Mn and GFsupported composite, with a strong P-O covalent tie occurring at the surface of the material, leading to a high degree of polarization and very low relaxation time. The CoMn(PO 4 ) 2 /GF material tested as a half-cell could achieve a specific capacity of 58.15 mAh g À1 at 0.5 A g À1 . A CoMn(PO 4 ) 2 /GF//activated carbon (AC) hybrid device was made up considering CoMn(PO 4 ) 2 /GF and an AC material as positive and negative electrodes, respectively. The CoMn(PO 4 ) 2 /GF//AC hybrid device achieved a specific capacity of 45.89 mAh g À1 , specific energy of 51.53 Wh kg À1 and a corresponding specific power of 561.52 W kg À1 at 0.5 A g À1 . Furthermore, the device displayed a 95% capacity retention after 10 000 GCD cycles at 12 A g À1 and showed improved performance over its initial specific capacity after a voltage holding test for over 110 hours at 2 A g À1 .

Urea-Assisted Nickel-Manganese Phosphate Composite Microarchitectures with Ultralong Lifecycle for Flexible Asymmetric Solid-State Supercapacitors: A Binder-Free Approach

“…The Ni 2p spectrum shows two main peaks of Ni 2p 3/2 (856.7 eV) and Ni 2p 1/2 (874.5 eV), along with corresponding satellite peaks (named “Sat”) at 862.1 and 880.4 eV, as seen in Figure b. The main peaks indicate the existence of the Ni 2+ oxidation state in the NMP-4 thin film. , Moreover, Figure c shows that the two intense peaks of Mn 2p 3/2 at 641.1 eV and Mn 2p 1/2 at 653.2 eV are associated with the oxidation states of Mn 2+ , while also two shakeup satellite peaks were detected at 644.9 and 656.9 eV . Furthermore, the P 2p spectrum (Figure d) exhibits a sharp peak at 133.7 eV, which is representative of the phosphate (PO 4 ) 3– group …”

“…6,53 Moreover, Figure 2c shows that the two intense peaks of Mn 2p 3/2 at 641.1 eV and Mn 2p 1/2 at 653.2 eV are associated with the oxidation states of Mn 2+ , while also two shakeup satellite peaks were detected at 644.9 and 656.9 eV. 54 Furthermore, the P 2p spectrum (Figure 2d) exhibits a sharp peak at 133.7 eV, which is representative of the phosphate (PO 4 ) 3− group. 55 56 The results of XRD, FTIR, Raman, and XPS confirm that the Ni−Mn phosphate composite materials were well prepared on the NF substrate.…”

Role of dual redox additivesKI/VOSO4in manganese ammonium phosphate at graphene quantum dots for supercapattery

“…Among the calculated values of C, 596 Fg −1 at 1 Ag −1, which is observed for MnAP at 75 mg GQD, which is higher than the other C values of the hybrid electrodes as presented in Table 1. The increase in C may be accounted for the increase in concentration mass dispersoid GQD enhancing surface coordination with and Mn, improving NH 4 + ion coupling with the manganese phosphate layers via hydrogen bonding and resulting in better ionic transport 30,62,63 …”

“…+ ion coupling with the manganese phosphate layers via hydrogen bonding and resulting in better ionic transport. 30,62,63 Figure 6D illustrates the GCD profile of MnAP@GQD3 at different current densities from 1 to 20 Ag À1 in 2M H 2 SO 4 . It is observed that the electrode at different current densities show isosceles contour suggesting its double-layer behavior from 1.0 to 0.6 V and from 0.6 to 0 V potential, it exhibits pseudocapacitance.…”

Performance evaluation of coated carbon foam material in heat exchanger applications

“…They discovered that the new sheets display higher specific surface area and large pore volume. Recently, Mirghni et al 21 investigated the synergy between Co, Mn, and Graphene foam‐supported composite to reach a high degree of polarization and very low relaxation time. In another work, a procedure for the ideal design of multilayer thermal protection was presented 22 .…”