@article {47341, title = {Bimetallic ZnFe2O4 nanosheets prepared via electrodeposition as binder-free high-performance supercapacitor electrodes}, journal = {Applied Surface Science}, volume = {559}, year = {2021}, month = {SEP }, pages = {149951}, type = {Article}, abstract = {

Binder-free bimetallic ZnFe2O4 nanosheets were fabricated using one-step electrodeposition, which facilitated excellent electrical contact between the ZnFe2O4 nanosheets and the nickel substrate. The resultant numerous ZnFe2O4 nanosheets with their cubic spinel structures promote interfacial activity to enhance the electrochemical and Faradaic redox reactions. The metallic Zn and Fe from the cubic spinel structure of ZnFe2O4 attract electrolytic ions and increase the energy-storage capability, thus yielding a specific capacitance of 1093 F.g(-1) at a current rate of 1 A.g(-1). Different samples were prepared by varying the amount of metal salts in the electrodeposition solution while maintaining a constant ZnNt:FeSO4 concentration ratio of 1:2 for all cases. The optimal electrode composition, which yielded an energy density of 54 Wh.kg(-1) and a capacitance retention of 93.5\% at N = 5000 charge-discharge cycles, was identified.

}, keywords = {Bimetallic, Electrodeposition, Energy storage device, supercapacitor, ZnFe2O4 nanosheet}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2021.149951}, author = {Joshi, Bhavana and Samuel, Edmund and Park, Chanwoo and Kim, Yongil and Lee, Hae-Seok and Yoon, Sam S.} } @article {48412, title = {Electrospun zinc-manganese bimetallic oxide carbon nanofibers as freestanding supercapacitor electrodes}, journal = {International Journal of Energy Research}, volume = {46}, year = {2022}, month = {DEC}, pages = {22100-22112}, type = {Article}, abstract = {

Flexible, lightweight, and freestanding zinc-manganese oxide carbon nanofibers are promising materials for the fabrication of portable electronic devices. Composite nanofibers were synthesized using terephthalic acid and sodium dodecyl sulfate. Terephthalic acid improves the flexibility of the composite fibers and facilitates the diffusion of electrolytic ions. Meanwhile, sodium dodecyl sulfate aids to elevate the metal (zinc) oxide particles to the surface of the nanofibers during annealing. The texturing of the carbon nanofiber surface with ZnO enhances the electrochemical activity of the composite fibers. Parametric studies were conducted by varying the weight ratio of zinc and manganese acetates from zero to unity. The optimal case with a ratio of 0.75 produces specific capacitances of 1080 and 817 F center dot g(-1) at current densities of 1 and 10 A center dot g(-1), respectively, with a wide potential window of 1.6 V, indicating outstanding energy storage capabilities. The capacitance retention was 92\% after 10 000 galvanostatic charge-discharge cycles. The bending angle test confirmed the mechanical durability of the freestanding carbon nanofiber electrodes, and the corresponding change in the cyclic voltammetry curve was negligible.

}, keywords = {electrospinning, freestanding electrode, high-energy-density, supercapacitor, ZnMn2O4}, issn = {0363-907X}, doi = {10.1002/er.7719}, author = {Joshi, Bhavana and Samuel, Edmund and Kim, Yongil and Kim, Taegun and El-Newehy, Mohamed and Aldalbahi, Ali and Yoon, Sam S.} } @article {48226, title = {Review of recent progress in electrospinning-derived freestanding and binder-free electrodes for supercapacitors}, journal = {Coordination Chemistry Reviews}, volume = {460}, year = {2022}, month = {JUN }, pages = {214466}, type = {Review}, abstract = {

The versatile electrospinning technique is scalable and suitable to fabricate highly conducting freestanding carbon nanofiber composite electrodes for energy storage devices. Freestanding/flexible electrodes hold enormous potential for use in wearable electronic devices. Carbon-yielding polymers and the optimal use of sacrificial polymers, metal oxides, and sulfides retain the flexibility and enhance the surface area and pseudocapacitance of electrodes. Both as-prepared electrospun fibers and carbonized nanofibers are compatible with surface decoration via various chemical and electrochemical routes. Metal oxides/sulfides with various morphologies, such as nanocones and nanosheets, can be grown on the carbon nanofibers or on the as-prepared electrospun fibers using chemical synthesis methods such as electro-deposition, hydrothermal processes, and chemical impregnation to enhance the pseudocapacitance of the electrodes. Similarly, the deposition of metal organic frameworks on as-prepared electrospun fibers embellishes these fibers with nanostructures of specific morphologies such as dodecahedral and spindle-shaped structures. Under optimal conditions, these morphologies do not hamper the flexibility of the fibers, and binders are not required to retain them or maintain the electrode integrity. The engineering of electrodes with various morphologies and process parameters is presented systematically. Electrospinning-derived electrodes that have demonstrated significant electrochemical performance are highlighted and critically analyzed, and the energy storage mechanisms of these supercapacitors are described in detail. (C) 2022 Elsevier B.V. All rights reserved.

}, keywords = {Carbon nanofibers, Co-axial, composites, core-shell, electrospinning, Flexible, Porous, supercapacitor}, issn = {0010-8545}, doi = {10.1016/j.ccr.2022.214466}, author = {Joshi, Bhavana and Samuel, Edmund and Kim, Yong-il and Yarin, Alexander L. and Swihart, Mark T. and Yoon, Sam S.} }