Morphological Modulation of Conducting Polymer Nanocomposites with Nickel Cobaltite/Reduced Graphene Oxide and Their Subtle Effects on the Capacitive Behaviors

Abstract

This work reports on the urchin-like architecture-based nickel cobaltite (NiCo 2 O 4 )/reduced graphene oxide (rGO)/conducting polymer [polyaniline (PANI) or polypyrrole (PPy)] nanocomposites prepared through a hydrothermal synthesis procedure, followed by in situ polymerization techniques. Subsequently, these materials are subjected to electrochemical investigation to search for promising electrode materials for energy storage applications. Interestingly, the morphology of NiCo 2 O 4 varies upon the addition of rGO as well as nitrogen-doped rGO (N-rGO). When it is composite with rGO, it forms an urchin-like architecture, and with N-rGO, it forms nanoparticle structures having a diameter of 90 ± 10 nm. Further, these nanostructures are intricately coated by conducting polymers (such as PANI and PPy) as evidenced from the field emission scanning electron microscopy and high-resolution transmission electron microscopy observations, and the overall shape does not alter after the modification. All composites are investigated thoroughly by Fourier transform infrared, Raman, X-ray powder diffraction, and X-ray photoelectron spectroscopies to confer the formation and presence of polymers. The NiCo 2 O 4 /rGO/PPy nanocomposites exhibit an excellent specific capacitance of 1547 ± 5 F/g at a current density of 0.5 A/g, a better energy density of 34.37 ± 0.11 W h/kg at 0.5 A/g, a notable power density of 99.98 ± 0.31 W/kg at 0.5 A/g, and retains its 94 ± 1% specific capacitance after 5000 charge− discharge cycles. The uniform coating over the urchin-like architecture by conducting polymers constructs a typical morphology, and possibly, it is the key factor behind gaining such superior electrochemical behavior owing to (a) the enhancement of surface area and (b) the combination of double-layer capacitive and pseudocapacitive properties. Furthermore, a symmetric flexible supercapacitor device made of NiCo 2 O 4 /rGO/PPy nanocomposites provides superior electrochemical behavior.

Facial Synthesis of Fe3O4/PPy Core–Shell Composite Electrode Material for Boosted Supercapacity

“…The FP-300 composite can provide an energy density of 96.8 Wh kg –1 at 500 W kg –1 . Although the power density is increased to 5000 W kg –1 , it shows an energy density of 47.6 Wh kg –1 , which is better than those of most electrode materials, such as NiCo 2 O 4 /rGO/PPy (34.37 Wh kg –1 at 100 W kg –1 ), Fe 3 O 4 /PANI (52.4 Wh kg –1 at 400 W kg –1 ), PPy/rGO/melamine (58.7 Wh kg –1 at 252.3 W kg –1 ), PPy/MGO (8.49 Wh kg –1 at 149.1 W kg –1 ), GO-PPy-Ag (25.5 Wh kg –1 at 399.1 W kg –1 ), co-axial nanocomposite (36 Wh kg –1 at 500 W kg –1 ), and Ag/PPy (43.9 Wh kg –1 at 50 W kg –1 ) . These outstanding characteristics fully prove the advantages of the Fe 3 O 4 /PPy core–shell composite with the 1D chain structure.…”

Challenges and Opportunities: Conducting Polymer‐Graphene based Nanocomposites of Metal Oxides and Metal Sulfides for Supercapacitors

“…The prevailing outcome of the NiCo 2 O 4 -rGO-PPy is due to its lower ESR (1.18 Ω) caused by the urchin-like morphology (which facilitated the ion transportation), rGO restacking prevention by NiCo2O4, and the collective effect of the individual constituents. [67] Polyaniline (PANI) and MnO 2 doped rGO based ternary composite (rGO-PANI-MnO 2 or RPM) reported Pravin H. Wadekar's et al for productive supercapacitor electrodes. For RPM composite preparation, the reduction, polymerization, and doping of MnO 2 were attained by a 1-step proficient and effortless synthetic technique.…”

“…The device exhibited a maximum 157 F g −1 (at 0.5 A g −1 ) specific capacitance, with 87.22 Wh kg −1 Ed at 499.85 W kg −1 power density. The prevailing outcome of the NiCo 2 O 4 ‐rGO‐PPy is due to its lower ESR (1.18 Ω) caused by the urchin‐like morphology (which facilitated the ion transportation), rGO restacking prevention by NiCo2O4, and the collective effect of the individual constituents [67] …”

Review of Polymeric Nanocomposites for Photocatalytic Wastewater Treatment

“…(a) Probable scheme for synthesis of NCO/rGO/PPy nanocomposite. Reproduced with permission from ref . Copyright 2020, American Chemical Society.…”