Chuxin Wu

An effective integrated design for enhanced cathodes of Ni foam-supported Pt/carbon nanotubes for Li-O2 batteries.

Designing an effective microstructural cathode combined with a highly efficient catalyst is essential for improving the electrochemical performance of Li-O2 batteries (LOBs), especially for long-term cycling. We present a nickel foam-supported composite of Pt nanoparticles (NPs) coated on self-standing carbon nanotubes (CNTs) as a binder-free cathode for LOBs. The assembled LOBs can afford excellent electrochemical performance with a reversible capacity of 4050 mAh/g tested at 20 mA/g and superior cyclability for 80 cycles with a limited capacity of 1500 mAh/g achieved at a high current density of 400 mA/g. The capacity corresponds to a high energy density of ∼3000 Wh/kg. The improved performance should be attributed to the excellent catalytic activity of highly dispersed Pt NPs, facile electron transport via loose CNTs connected to the nickel foam current collector, and fast O2 diffusion through the porous Pt/CNTs networks. In addition, some new insights from impedance analysis have been proposed to explain the enhanced mechanism of LOBs.

Long cycling life of Li2MnSiO4 lithium battery cathodes under the double protection from carbon coating and graphene network

Li2MnSiO4 possesses a high theoretical capacity of 332 mA h g−1 as a lithium battery cathode, but it suffered from rapid capacity fading due to the structural instability and manganese dissolution during cycles. Herein, we developed a unique reduced graphene oxide (RGO)@Li2MnSiO4@C composite as a cathode material for lithium ion batteries. Under the double protection from RGO and carbon coating, Li2MnSiO4 demonstrated outstanding electrochemical performance with a high capacity of 290 mA h g−1 at 0.05 C, and a long cycling life up to 700 cycles at 1 C.

In situ generation of Li2FeSiO4 coating on MWNT as a high rate cathode material for lithium ion batteries

In this report, a novel MWNT@Li2FeSiO4 coaxial nanocable was designed and used as a superior cathode material for lithium ion batteries. The shell Li2FeSiO4 delivered excellent rate performance with a high capacity of 180 mA h g−1 which remained after 120 cycles at 1 C.

Binder-Free Manganese Oxide/Carbon Nanomaterials Thin Film Electrode for Supercapacitors

A ternary thin film electrode was created by coating manganese oxide onto a network composed of single-walled carbon nanotubes and single-walled carbon nanohorns. The electrode exhibited a porous structure, which is a promising architecture for supercapacitors applications. The maximum specific capacitances of 357 F/g for total electrode at 1 A/g were achieved in 0.1 M Na(2)SO(4) aqueous solution.

A layered porous ZrO2/RGO composite as sulfur host for lithium-sulfur batteries

A new layered porous nanostructure with ZrO2 nanoparticles attached on the reduced graphene oxide (ZrO2/RGO) was synthesized by a facile solvothermal process. The resulting ZrO2/RGO composite with well-designed mesoporous structure and excellent conductivity not only served as scaffold to house sulfur but also as polysulfide reservoir for lithium–sulfur batteries. This nanostructured S@ZrO2/RGO electrode exhibits enhanced cycling stability, high specific capacity, and superior coulombic efficiency.

A general strategy for synthesis of metal oxide nanoparticles attached on carbon nanomaterials

We report a general strategy for synthesis of a large variety of metal oxide nanoparticles on different carbon nanomaterials (CNMs), including single-walled carbon nanotubes, multi-walled carbon nanotubes, and a few-layer graphene. The approach was based on the π-π interaction between CNMs and modified aromatic organic ligands, which acted as bridges connecting metal ions and CNMs. Our methods can be applicable for a large variety of metal ions, thus offering a great potential application.

Porous cobalt–nitrogen-doped hollow graphene spheres as a superior electrocatalyst for enhanced oxygen reduction in both alkaline and acidic solutions

Porous cobalt–nitrogen-doped hollow graphene spheres were prepared by a template synthesis method. As a catalyst for the oxygen reduction reaction, they exhibit an excellent electrocatalytic activity, superior methanol tolerance and strong durability, not only in alkaline solution, but also in acidic solution. The unprecedented electrocatalytic performance of the catalyst is attributed to the well-defined morphology, high specific surface area (321 m2 g−1), large pore volume (1.8 cm3 g−1) and homogeneous distribution of cobalt–nitrogen active sites.

Pt2SnCu nanoalloy with surface enrichment of Pt defects and SnO2 for highly efficient electrooxidation of ethanol

We artfully synthesized Pt defects and SnO2 on the surface of a carbon-supported Pt2SnCu nanoalloy (Pt2SnCu–O-A/C) by in situ surface oxidation and acid treatment. The Pt2SnCu–O-A/C modified in this way exhibits excellent electrocatalytic activities for the ethanol oxidation reaction (EOR) in comparison to the commercial Pt/C and PtRu/C. The surface activity and mass activity are, respectively, 3.1 and 4.3 times greater than those of Pt/C. The enhanced activity for ethanol oxidation is attributed to the synergistic catalytic effect of Pt defects and SnO2.

MnO2 Nanofilms on Nitrogen-Doped Hollow Graphene Spheres as a High-Performance Electrocatalyst for Oxygen Reduction Reaction

Platinum is commonly chosen as an electrocatalyst used for oxygen reduction reaction (ORR). In this study, we report an active catalyst composed of MnO2 nanofilms grown directly on nitrogen-doped hollow graphene spheres, which exhibits high activity toward ORR with positive onset potential (0.94 V vs RHE), large current density (5.2 mA cm-2), and perfect stability. Significantly, when it was used as catalyst for air electrode, a zinc-air battery exhibited a high power density (82 mW cm-2) and specific capacities (744 mA h g-1) comparable to that with Pt/C (20 wt %) as air cathode. The enhanced activity is ascribed to the synergistic interaction between MnO2 and the doped hollow carbon nanomaterials. This easy and cheap method paves a way of synthesizing high-performance electrocatalysts for ORR.

Strong-coupled Co-g-C3N4/SWCNTs composites as high-performance electrocatalysts for oxygen reduction reaction

The hybrid materials of cobalt doped graphitic carbon nitride (g-C3N4) attached on single-walled carbon nanotubes (SWCNTs) were synthesized by a simple pyrolysis process. Electrochemical measurements revealed that the composites exhibited excellent electrocatalytic activity for oxygen reduction reaction (ORR), with a more positive onset potential (−0.03 V), half-wave potential (−0.15 V), high efficiency four-electron process (n = 3.97) and much higher stability than that of commercial Pt/C catalysts in alkaline media. The ORR activity mainly originates from the strong coupling of Co-g-C3N4 derived active sites on the SWCNTs.