A facile one-step method was demonstrated for the electrodeposition of manganese−nickel sulfide (Mn−Ni−S) 3D interconnected sheets on nickel foam substrates. The assynthesized materials were characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) techniques. Upon their use as supercapacitor electrodes, the electrodeposited Mn−Ni−S showed exceptionally high specific capacitance (2849 and 1986 F/g at 1 and 5 A/g, respectively) and an excellent rate capability. Using Fe 3 O 4 -GR as the negative electrode and the Mn−Ni−S 3D interconnected sheets as the positive electrode to assemble an asymmetric supercapacitor device revealed high power density (800 W kg −1 ) and energy density (40.44 Wh kg −1 ) with 90% capacitance retention and a Columbic efficiency of 100% after 11 000 cycles, indicating the high potential of the fabricated materials for practical energy storage devices.

Supercapacitors (SCs) are being considered the next-generation power storage devices due to the many favorable properties. In this regard, mesoporous nanostructures are excellent supercapacitor electrodes as they enjoy a large number of active sites and high surface area promising the utilization of the full capacitance of the active materials. In this study, we report on the assembly of electrospun, binder-free mesoporous Mn 0.56 V 0.42 O@C fibrous electrodes. The morphological and structural analyses of the fabricated Mn 0.56 V 0.42 O@C electrodes were investigated using field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and glancing angle X-ray diffraction (GAXRD). The X-ray photoelectron spectroscopy (XPS) and GAXRD confirm the formation of Mn 0.56 V 0.42 O nanofibers and their successful bonding to carbon during crystal growth. Those fibrous composite electrodes showed excellent specific capacitance of 668.5 F g −1 at 1 A g −1 . The highly obtained capacitance is attributed to the multiple oxidation states of the Mn−V oxides, the binder-free electrodes, surface roughness, and the mesoporous nature of the fabricated nanofibers. The asymmetric supercapacitor composed of the mesoporous Mn 0.56 V 0.42 O@C nanofibers as the positive electrode and graphene hydrogel as the negative electrode possesses ultrahigh energy density of 37.77 W h kg −1 and a power density of 900 W kg −1 with superior Coulombic efficiency over 13 000 charge−discharge cycles.

The intensive implementation of Li‐ion batteries in many markets makes it increasingly urgent to address the recycling of strategic materials from spent batteries. Batteries typically contain toxic chemicals and cannot be disposed of at will. In this study, Li−Ni−Mn−Co hydroxides are successfully recycled from spent Li‐ion batteries electrodeposited on nickel foam, and fully characterized using different techniques such as field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), energy dispersive X‐ray spectroscopy (EDXS), inductively coupled plasma (ICP), and X‐ray photoelectron spectroscopy (XPS) techniques. The recycled nanostructured films are tested in a three‐electrode electrochemical system to investigate their capacitance behavior. The recycled electrodes show high capacitance of 951 F g−1 (specific capacity of 523.5 C g−1) at 1 A g−1. Moreover, the recycled materials are used as positive electrodes to construct asymmetric supercapacitor devices. The device shows a coulombic efficiency of 100 %, a capacitance retention reaching approximately 90 % with excellent cycling stability after 10 000 cycles as well as reasonable power and energy densities.

The use of titanium dioxide nanotubes in the powder form (TNTP) has been a hot topic for the past few decades in many applications.

We demonstrate the fabrication of binder-free electrospun nickel− manganese oxides embedded into carbon-shell fibrous electrodes. The morphological and structural properties of the assembled electrode materials were elucidated by high-resolution transmission electron microscopy (HR-TEM), field-emission scanning electron microscopy, and glancing-angle X-ray diffraction. The fibrous structure of the electrodes was retained even after annealing at high temperatures. The X-ray photoelectron spectroscopy and HR-TEM analyses revealed the formation of nickel and manganese oxides in multiple oxidation states (Ni 2+ , Ni 3+ , Mn 2+ , Mn 3+ , and Mn 4+ ) embedded in the carbon shell. The embedded nickel−manganese oxides into the carbon matrix fibrous electrodes exhibit an excellent capacitance (1082 F/g) in 1 M K 2 SO 4 at 1 A/g and possess a high rate capability of 73% at 5 A/g. The high rate capability and capacitance can be attributed to the presence of carbon crosslinked channels, the binder-free nature of the electrodes, and various oxidation states of the Ni−Mn oxides. The asymmetric supercapacitor device constructed of the asfabricated nanofibers and the bio-derived microporous carbon as the positive and negative electrodes, respectively, sustains up to 1.9 V with a high specific capacitance at 1.5 A/g of 108 F/g. The nanofibrous//bio-derived device exhibits an outstanding specific energy of 54.2 W h/kg with a high specific power of 1425 W/kg. Interestingly, the tested device maintains a high capacitive retention of 92% upon cycling over 10,000 charging/discharging cycles.

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