Xia Cui

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.

Core–shell-structured Li3V2(PO4)3 –LiVOPO4 nanocomposites cathode for high-rate and long-life lithium-ion batteries

A facile strategy has been developed to construct unique core–shell-structured Li2.7V2.1(PO4)3 nanocomposites with a Li3V2(PO4)3 core and LiVOPO4 shell by using nonstoichiometric design and high-energy ball milling (HEBM) treatment. The HEBM treatment supplies enough energy to drive the excess V atoms to the surface to form a V-enriched shell. Such kind of cathode can deliver a high reversible capacity of 131.5 mA h g−1 at 0.5C, which is close to the theoretical capacity (133 mA h g−1 in 3.0–4.3 V). Even at 20C, it still delivers an excellent discharge capacity of 116.3 mA h g−1, and a remarkable capacity of 111.0 mA h g−1 after 1000 cycles, corresponding to an ultra-small capacity-loss of 0.0046% per cycle. The significantly improved high-rate electrochemical performance can be attributed to the active shell of LiVOPO4, which not only efficiently facilitates the electron and Li+ ion transport during cycling processes, but also accommodates more Li+ ions to effectively compensate the capacity loss of the core.

Carbon nanotube entangled Mn3O4 octahedron as anode materials for lithium-ion batteries.

A nanocomposite of Mn3O4 octahedrons entangled by carbon nanotubes (CNTs) was synthesized by a hydrothermal method assisted with a non-ionic surfactant. The integration of octahedral structure and CNTs could offer many critical features, which are needed for high activity anodes, such as fast ion diffusion, good electronic conductivity, and skeleton supporting function, thus enabling the nanocomposite-based anodes with excellent electrochemical performance. In addition, CNTs can not only serve as the conductive network and structure skeleton to improve the anode performance, but also play an indispensable role in the formation of more uniform Mn3O4 octahedrons. The lithium-ion batteries based on the CNTs-entangled Mn3O4 octahedrons delivered a high capacity of over 800 mAh g-1 at a current density of 0.2 C for 200 cycles, and even as high as 678.4 mAh g-1 when cycled at 0.5 C after 400 cycles, exhibiting a high capability and ultralong cycle life.