Building Robust Carbon Nanotube-Interweaved-Nanocrystal Architecture for High-Performance Anode Materials

Rational design of electrode materials is essential but still a challenge for lithium-ion batteries. Herein, we report the design and fabrication of a class of nanocomposite architecture featured by hierarchically structured composite particles that are built from iron oxide nanocrystals and carbon nanotubes. An aerosol spray drying process was used to synthesize this architecture. Such nanoarchitecture enhanced the ion transport and conductivity that are required for high-power anodes. The large volume changes of the anodes during lithium insertion and extraction are accommodated by the particle’s resilience and internal porosity. High reversible capacities, excellent rate capability, and stable performance are attained. The synthesis process is simple and broadly applicable, providing a general approach toward high-performance energy storage materials

High-Performance Sodium-Ion Pseudocapacitors Based on Hierarchically Porous Nanowire Composites

Electrical energy storage plays an increasingly important role in modern society. Current energy storage methods are highly dependent on lithium-ion energy storage devices, and the expanded use of these technologies is likely to affect existing lithium reserves. The abundance of sodium makes Na-ion-based devices very attractive as an alternative, sustainable energy storage system. However, electrodes based on transition-metal oxides often show slow kinetics and poor cycling stability, limiting their use as Na-ion-based energy storage devices. The present paper details a new direction for electrode architectures for Na-ion storage. Using a simple hydrothermal process, we synthesized interpenetrating porous networks consisting of layer-structured V₂O₅ nanowires and carbon nanotubes (CNTs). This type of architecture provides facile sodium insertion/extraction and fast electron transfer, enabling the fabrication of high-performance Na-ion pseudocapacitors with an organic electrolyte. Hybrid asymmetric capacitors incorporating the V₂O₅/CNT nanowire composites as the anode operated at a maximum voltage of 2.8 V and delivered a maximum energy of ∼40 Wh kg^–1, which is comparable to Li-ion-based asymmetric capacitors. The availability of capacitive storage based on Na-ion systems is an attractive, cost-effective alternative to Li-ion systems

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