In this paper, we reported an effective and simple strategy to prepare large areal mass loading of MnO2 on porous graphene gel/Ni foam (denoted as MnO2/G-gel/NF) for supercapacitors (SCs). The MnO2/G-gel/NF (MnO2 mass: 13.6 mg cm(-2)) delivered a large areal capacitance of 3.18 F cm(-2) (234.2 F g(-1)) and good rate capability. The prominent electrochemical properties of MnO2/G-gel/NF are attributed to the enhanced conductivities and improved accessible area for ions in electrolytes. Moreover, an asymmetric supercapacitor (ASC) based on MnO2/G-gel/NF (MnO2 mass: 6.1 mg cm(-2)) as the positive electrode and G-gel/NF as the negative electrode achieved a remarkable energy density of 0.72 mW h cm(-3). Additionally, the fabricated ASC device also exhibited excellent cycling stability, with less than 1.5% decay after 10,000 cycles. The ability to effectively develop SC electrodes with high mass loading should open up new opportunities for SCs with high areal capacitance and high energy density.

No abstract

The SiO-based composites containing different carbon structures were prepared from asphalt and graphite by the milling, spray drying, and pyrolysis. In the obtained near-spherical composite particles, the refined amorphous SiO plates, which are coated with an amorphous carbon layer, are aggregated with the binding of graphite sheets. The SiO/C/Graphite composites present a maximum initial charge capacity of 963 mAh g −1 at 100 mA g −1 , excellent cyclic stability (∼950 mAh g −1 over 100 cycles), and rate capability with the charge capacity of 670 mAh g −1 at 1,000 mA g −1 . This significant improvement of electrochemical performances in comparison with pristine SiO or SiO/C composite is attributed to the unique microstructure, in which both the graphite sheets and amorphous carbon coating could enhance the conductivity of SiO and buffer the volume change of SiO. The higher pyrolysis temperature causes the denser spherical microstructure and better cycle life. Our work demonstrates the potential of this SiO/C/Graphite composite for high capacity anode of LIBs.

No abstract

No abstract