Binder-free and full electrical-addressing free-standing nanosheets with carbon nanotube fabrics for electrochemical applications

Three-dimensional layer-by-layer anode structure based on Co3O4 nanoplates strongly tied by capillary-like multiwall carbon nanotubes for use in high-performance lithium-ion batteries

A layer-by-layer (LBL) structure composed of Co3O4 nanoplates and capillary-like three-dimensional (3D) multiwall carbon nanotube (MWCNT) nets was developed as an anode with simultaneous high-rate and long-term cycling performance in a lithium-ion battery. As the current density was increased to 50 A g(-1), the LBL structure exhibited excellent long-term cycling and rate performance. Thus, the Co3O4 nanoplates were in good electrical contact with the capillary-like 3D MWCNT nets under mechanically severe strain during long-term, high-rate cyclic operation.

Three-dimensional mesoscale heterostructures of ZnO nanowire arrays epitaxially grown on CuGaO2 nanoplates as individual diodes

We report a three-dimensional (3D) mesoscale heterostructure composed of one-dimensional (1D) nanowire (NW) arrays epitaxially grown on two-dimensional (2D) nanoplates. Specifically, three facile syntheses are developed to assemble vertical ZnO NWs on CuGaO2 (CGO) nanoplates in mild aqueous solution conditions. The key to the successful 3D mesoscale integration is the preferential nucleation and heteroepitaxial growth of ZnO NWs on the CGO nanoplates. Using transmission electron microscopy, heteroepitaxy was found between the basal planes of CGO nanoplates and ZnO NWs, which are their respective (001) crystallographic planes, by the observation of a hexagonal Moiré fringes pattern resulting from the slight mismatch between the c planes of ZnO and CGO. Careful analysis shows that this pattern can be described by a hexagonal supercell with a lattice parameter of almost exactly 11 and 12 times the a lattice constants for ZnO and CGO, respectively. The electrical properties of the individual CGO-ZnO mesoscale heterostructures were measured using a current-sensing atomic force microscopy setup to confirm the rectifying p-n diode behavior expected from the band alignment of p-type CGO and n-type ZnO wide band gap semiconductors. These 3D mesoscale heterostructures represent a new motif in nanoassembly for the integration of nanomaterials into functional devices with potential applications in electronics, photonics, and energy.

Folded structured graphene paper for high performance electrode materials

A novel method to fabricate graphene paper with folded structured graphene sheets is described. When used as an electrode for LIBs and supercapacitors, the as-prepared graphene paper can show much higher performances compared to conventional graphene paper fabricated by a flow-directed assembly method. The unique graphene paper obtained here is promising to act as a new kind of flexible electrode for wearable or rolling-up devices.