Wei-Min Chen

Nitrogen-doped porous carbon nanofiber webs as anodes for lithium ion batteries with a superhigh capacity and rate capability.

Nitrogen-doped carbon nanofiber webs (CNFWs) with high surface areas are successfully prepared by carbonization-activation of polypyrrole nanofiber webs with KOH. The as-obtained CNFWs exhibit a superhigh reversible capacity of 943 mAh g(-1) at a current density of 2 A g(-1) even after 600 cycles, which is ascribed to the novel porous nanostructure and high-level nitrogen doping.

Synthesis of functionalized 3D hierarchical porous carbon for high-performance supercapacitors

Functionalized three-dimensional hierarchical porous carbon (THPC) is prepared via a facile modified chemical activation route with polypyrrole microsheets as precursor and KOH as activating agent. The as-obtained THPC presents a large specific surface area (2870 m2 g−1), high-level heteroatom doping (N: 7.7 wt%, O: 12.4 wt%), excellent electrical conductivity (5.6 S cm−1), and hierarchical porous nano-architecture containing macroporous frameworks, mesoporous walls and microporous textures. Such unique features make the THPC an ideal electrode material for electrochemical energy storage. As the electrode material for a supercapacitor, the THPC exhibits a high capacitance, excellent rate performance and long-term stability in both aqueous and organic electrolytes.

Sulfur‐Doped Carbon with Enlarged Interlayer Distance as a High‐Performance Anode Material for Sodium‐Ion Batteries

S‐doped carbon is investigated as a high‐performance anode material for sodium‐ion batteries. Due to the introduction of a high‐content of S atoms, the as‐obtained S‐doped carbon shows an enlarged interlayer distance. As an anode, a high specific capacity of up to 303 mAh g−1 is achieved, even after 700 cycles at 0.5 A g−1.

Controllable Synthesis of Hollow Bipyramid β-MnO2 and Its High Electrochemical Performance for Lithium Storage

Three types of MnO2 nanostructures, viz., α-MnO2 nanotubes, hollow β-MnO2 bipyramids, and solid β-MnO2 bipyramids, have been synthesized via a simple template-free hydrothermal method. Cyclic voltammetry and galvanostatic charge/discharge measurements demonstrate that the hollow β-MnO2 bipyramids exhibit the highest specific capacity and the best cyclability; the capacity retains 213 mAh g(-1) at a current density of 100 mA g(-1) after 150 cycles. XRD patterns of the lithiated β-MnO2 electrodes clearly show the expansion of lattice volume caused by lithiation, but the structure keeps stable during lithium insertion/extraction process. We suggest that the excellent performance for β-MnO2 can be attributed to its unique electrochemical reaction, compact tunnel-structure and hollow architecture. The hollow architecture can accommodate the volume change during charge/discharge process and improve effective diffusion paths for both lithium ions and electrons.

Coordination of Surface-Induced Reaction and Intercalation: Toward a High-Performance Carbon Anode for Sodium-Ion Batteries

Oxygen‐rich carbon material is successfully fabricated from a porous carbon and evaluated as anode for sodium‐ion battery. With the strategy of optimal combination of fast surface redox reaction and reversible intercalation, the oxygen‐rich carbon anode exhibits a large reversible capacity (447 mAh g−1 at 0.2 A g−1), high rate capability (172 mAh g−1 at 20 A g−1), and excellent cycling stability.