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Biomass‐derived carbon materials are an amazing electrode material for supercapacitor, owing to their abundant, porous structure and composition. Herein, a controllable N content carbon material with hierarchical porous structure was fabricated via an integrated carbonization, activation and nitrogen‐doping process. N‐rich camellia pollen is used as carbon precursor, while NH4Cl is employed as both activation agent and dopant. The optimal N‐doped carbon with higher N content (3.82 at%), suitable pore size distribution and larger specific surface area (810 m2 g−1), provides abundant ion transport channels and exposes more accessible active sites. Thus, a high specific capacitance of 280 F g−1 (1 A g−1) in 6 M KOH (three‐electrode system) can be obtained with making full use of N−HPC‐1. Moreover, the assembled symmetrical supercapacitor delivers high energy densities both in 6 M KOH (13.3 Wh kg−1) and 1 M Na2SO4 (20 Wh kg−1) that can be used for LED lighting. More than that, it is also demonstrates excellent cycle stability in 6 M KOH (85.4% after 20000 cycles at 20 A g−1). In view of the above‐mentioned merits, this N‐doped hierarchical porous carbon is anticipated to be a promising material for application in supercapacitors and other fields. [ABSTRACT FROM AUTHOR]

In this work, we developed a simple one-step hydrothermal method to successfully prepare Fe3O4/FeS-reduced graphene oxide (Fe3O4/FeS/rGO) composite directly, which is a novel Lithium-ion batteries (LIBs) anode material. The characterization of Fe3O4/FeS/rGO composite demonstrates that octahedral Fe3O4/FeS particles are uniformly deposited on the rGO, leading to a strong synergy between them. The excellent structural design can make Fe3O4/FeS/rGO composite to have higher reversible capacity (744.7 mAh/g at 0.1 C after 50 cycles), excellent cycling performance and superior rate capability. This outstanding electrochemical behavior can be attributed to the conductivity network of rGO, which improves the composite electrode conductivity, facilitates the diffusion and transfer of ions and prevents the aggregation and pulverization of Fe3O4/FeS particles during the charging and discharging processes. Moreover, the Fe3O4/FeS/rGO electrode surface is covered with a thin solid-electrolyte interface (SEI) film and the octahedral structure of Fe3O4/FeS particles is still clearly visible, which indicates that composite electrode has excellent interface stability. We believe that the design of this composite structure will provide a new perspective for the further study of other transition metal oxides for LIBs. The Fe3O4/FeS-reduced graphene oxide (Fe3O4/FeS/rGO) composite was obtained using one-step hydrothermal method. Thereinto, octahedral Fe3O4/FeS particles are uniformly deposited on the rGO, leading to a strong synergy between them. With the advantages of excellent structure, the Fe3O4/FeS/rGO composite holds the prospective applications as an advanced anode material in LIBs. [ABSTRACT FROM AUTHOR]

• Octahedral Fe 3 O 4 /FeS has been synthesized by one pot hydrothermal method. • The formation mechanism of Fe 3 O 4 /FeS was proposed. • The Fe 3 O 4 /FeS exhibits a high capacity of 530.7 mAh g−1 after 100 cycles at 0.1 C. • Fe 3 O 4 /FeS causes a low electrolyte decomposition, and has a high conductivity. • Fe 3 O 4 /FeS still held stabilized octahedral structure after 100 cycles at 0.1 C. The booming development of rechargeable lithium-ion batteries puts forwards higher requirement for stable electrode material by a cost-effective method. Herein, Fe 3 O 4 /FeS composite with a regular octahedral structure was synthesized by a facile one-pot hydrothermal method for and was evaluated as anode material for lithium-ion batteries. As indicated by the morphology evolution, the presence of FeS can effectively alleviate volume expansion and inhibit the agglomeration the Fe 3 O 4 /FeS composite during the Li+ insertion/extraction process. Moreover, the introduction of FeS was proved to form a high-quality solid-electrolyte interface (SEI) film by reducing electrolyte decomposition. Benefitting from the artful design of anode material, the Fe 3 O 4 /FeS composite exhibited superior cycling performance with a high specific capacity of 530.7 mAh g−1 after 100 cycles at 0.1 C, which is much higher than that of pure Fe 3 O 4 (217 mAh g−1 after 100 cycle at 0.1 C). [ABSTRACT FROM AUTHOR]