Due to the growing demand for clean and renewable energy, the effective utilization of renewable resources in energy storage and has been concerned. And high specific capacitance and stable electrochemistry for energy storage devices are challenging to develop. Learning from unique structure of goniastrea coral, we design to construct three-dimensional layered conductive electrodes material made of MoS 2 @chitosan carbon spheres (MNCCS) composite. The NiCoLDH nanosheets construct on the surface of conductive chitosan carbon spheres to effectively form open permeable channels and rich conductive networks, improves the efficient energy storage and electrochemical stability. MoS 2 is strongly coupled with NiCoLDH nanosheets through heterointerface, which resembles tentacles on the surface of coral, exposing more active sites to efficiently trap ions. Besides, the obtained material possesses favorable heterojunction interface and defects, which provide sufficient available electroactive sites and numerous storage charge area. Hence, The MNCCS presents an outstanding specific capacitance of 2605.9 F g −1 at 1 A g −1 . Notably, a supercapacitor fitted with MNCCS electrode and CCS electrode achieves high specific capacitance (234.4 F g −1 at 1 A g −1 ), the maximum energy density of 77.0W h kg −1 at highest power density of 667.4W kg −1 , along with the excellent cycling stability of 90.8% retention over 10,000 cycles. This work provides a new perspective for fabricating high-performance and stable supercapacitors electrode material for clean energy storage.
The structural instability of metal oxides retards realizing high-performance and long lifespan supercapacitors . We prepare an electrochemical active heterostructure of NiCo layered double hydroxide (LDH) confined by carboxyl carbon nanotube (CNTCOOH). Through the electrostatic interactions between carboxyl groups (COO − ) of CNTCOOH and metal cations of LDH under a simple hydrothermal treatment , the CNTCOOH confined NiCoLDH (CNTCOOH- c -NiCoLDH) can be easily fabricated. The CNTCOOH- c -NiCoLDH demonstrates the specific morphology of rope-fastened plates and shows ultrahigh cycled stability. In addition, the hydrophilic carboxyl groups on CNTCOOH also regulates the interfacial electronic coupling and electrolyte soaking, resulting in high rate capability. The charge-storage capacitance of CNTCOOH- c -NiCoLDH heterostructures reaches 2120.8 F/g at 1 A/g. The devices of CNTCOOH- c -NiCoLDH//AC show both high energy density (171.0 Wh/kg) and high power density (950.0 W/kg), and have ultrahigh capacity retention rate of 93.64 % after 50,000 charge and discharge cycles at a high current density of 5 A/g. This work supports an effective confinement idea and a facile method that can be applied on a large scale for the design and fabrication of super high stable metal oxide-based supercapacitors .
This study presents a valuable repurposing approach for spent cathode carbon, in which the aluminum electrolysis spent cathode carbon was successfully converted into graphene oxide by Hummer’s method of oxidative intercalation with synergistic ultrasonic exfoliation, and further constructed NiCoLDH/rGO-SCC composites to be used in the electrode materials of hybrid supercapacitor. The large specific surface area of graphene oxide serves as a conductive channel in the electrodes, facilitating charge transfer during the reaction process, in addition to providing NiCoLDH nanosheets with a large number of spatial sites. Electrochemical tests and density functional theory calculations confirmed that graphene oxide facilitated charge transfer during pseudocapacitive reactions. In the three-electrode system, the composite exhibited a specific capacity of 2818 F g −1 , ensuring outstanding electrochemical performance for the hybrid supercapacitor. The results showed that the assembled hybrid supercapacitor could reach an energy density of 35.93 Wh kg −1 at a power density of 375 W kg −1 , and still possesses a capacity retention rate of 85.25 % after 1000 charge/discharge cycles. Consequently, the results demonstrated the supercapacitor’s significant application prospects. This approach provides a sustainable way to recycle spent cathode carbon and develop new capacitor electrode applications.
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