For the first time, we developed edge-rich and dopant-free graphene as a highly efficient ORR electrocatalyst. Electrochemical analysis revealed that the as-obtained edge-rich graphene showed excellent ORR activity through a one-step and four-electron pathway. With a similar strategy, edge-rich carbon nanotubes and graphite can also be obtained with enhanced ORR activity. This work confirms the important role of edge carbon in efficient ORR electrocatalysis without interruption by any other dopants.

Novel N, S co-doped graphene (NSG) was prepared by annealing graphene oxide with thiourea as the single N and S precursor. The NSG electrodes, as efficient metal-free electrocatalysts, show a direct four-electron reaction pathway, high onset potential, high current density and high stability for the oxygen reduction reaction.

Heteroatom-doped carbon materials have been extensively investigated as metal-free electrocatalysts to replace commercial Pt/C catalysts in oxygen reduction reactions in fuel cells and Li-air batteries. However, the synthesis of such materials usually involves high temperature or complicated equipment. Graphene-based sulfur composites have been recently developed to prolong the cycling life of Li-S batteries, one of the most attractive energy-storage devices. Given the high cost of graphene, there is significant demand to recycle and reuse graphene from Li-S batteries. Herein, we report a green and cost-effective method to prepare sulfur-doped graphene, achieved by the continuous charge/discharge cycling of graphene-sulfur composites in Li-S batteries. This material was used as a metal-free electrocatalyst for the oxygen reduction reaction and shows better electrocatalytic activity than pristine graphene and better methanol tolerance durability than Pt/C.

Fe 2 O 3 supported on nitrogen-doped graphene (Fe 2 O 3 /N-rGO) hydrogel was prepared by a facial one-pot hydrothermal method. The efficient Fe 2 O 3 loading and nitrogen doping of graphene was realized with this method. The morphology and structure of the samples were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, thermal gravimetric analysis, Raman spectra, X-ray diffraction, and nitrogen isothermal adsorption−desorption. The chemical environment of the surface composition of the samples was recorded by X-ray photoelectron spectroscopy. The electrochemical performance was tested with a three-electrode system in the aqueous electrolyte of 1 M KOH. The electrochemical measurement demonstrated that Fe 2 O 3 /N-rGO shows a specific capacitance as high as 618 F g −1 at a discharge current density of 0.5 A g −1 . Even at the current density of 10 A g −1 , the specific capacitance is still as high as 350 F g −1 . After 5000 cycles, the capacity retention is still maintained at 56.7%.

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A facile vacuum filtration method is applied for the first time to construct sandwich-structure anode. Two layers of graphene stacks sandwich a composite of black phosphorus (BP), which not only protect BP from quickly degenerating but also serve as current collector instead of copper foil. The BP composite, reduced graphene oxide coated on BP via chemical bonding, is simply synthesized by solvothermal reaction at 140 °C. The sandwiched film anode used for lithium-ion battery exhibits reversible capacities of 1401 mAh g during the 200th cycle at current density of 100 mA g indicating superior cycle performance. Besides, this facile vacuum filtration method may also be available for other anode material with well dispersion in N-methyl pyrrolidone (NMP).

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We constructed defective heterointerfaces of p-SnO on n-SnS2 nanosheets by plasma treatment to improve the anode performance in Li-ion batteries.