Building Robust Architectures of Carbon and Metal Oxide Nanocrystals toward High-Performance Anodes for Lithium-Ion Batteries

Design and fabrication of effective electrode structure is essential but is still a challenge for current lithium-ion battery technology. Herein we report the design and fabrication of a class of high-performance robust nanocomposites based on iron oxide spheres and carbon nanotubes (CNTs). An efficient aerosol spray process combined with vacuum filtration was used to synthesize such composite architecture, where oxide nanocrystals were assembled into a continuous carbon skeleton and entangled in porous CNT networks. This material architecture offers many critical features that are required for high-performance anodes, including efficient ion transport, high conductivity, and structure durability, therefore enabling an electrode with outstanding lithium storage performance. For example, such an electrode with a thickness of ∼35 μm could deliver a specific capacity of 994 mA h g^–1 (based on total electrode weight) and high recharging rates. This effective strategy can be extended to construct many other composite electrodes for high-performance lithium-ion batteries

Hierarchical Nanostructured WO₃ with Biomimetic Proton Channels and Mixed Ionic-Electronic Conductivity for Electrochemical Energy Storage

Protein channels in biologic systems can effectively transport ions such as proton (H⁺), sodium (Na⁺), and calcium (Ca⁺) ions. However, none of such channels is able to conduct electrons. Inspired by the biologic proton channels, we report a novel hierarchical nanostructured hydrous hexagonal WO₃ (<i>h</i>-WO₃) which can conduct both protons and electrons. This mixed protonic–electronic conductor (MPEC) can be synthesized by a facile single-step hydrothermal reaction at low temperature, which results in a three-dimensional nanostructure self-assembled from <i>h</i>-WO₃ nanorods. Such a unique <i>h</i>-WO₃ contains biomimetic proton channels where single-file water chains embedded within the electron-conducting matrix, which is critical for fast electrokinetics. The mixed conductivities, high redox capacitance, and structural robustness afford the <i>h</i>-WO₃ with unprecedented electrochemical performance, including high capacitance, fast charge/discharge capability, and very long cycling life (>50 000 cycles without capacitance decay), thus providing a new platform for a broad range of applications