Xiaolei Jiang

General synthesis of hollow MnO2, Mn3O4 and MnO nanospheres as superior anode materials for lithium ion batteries

The use of manganese oxides as promising candidates for anode materials in lithium ion batteries has attracted a significant amount of attention recently. Here, we develop a general approach to synthesize hollow nanospheres of MnO2, Mn3O4 and MnO, using carbon nanospheres as a template and a reagent. Depending on the calcination temperature, time and atmosphere, hollow nanospheres of MnO2 assembled by randomly dispersed nanosheets, or hollow nanospheres of Mn3O4 and MnO composed of aggregated nanoparticles, are produced. The electrochemical properties of the three hollow nanoparticles are investigated in terms of cycling stability and rate capability. They deliver the specific capacities of 840, 1165 or 1515 mA h g−1 after 60 cycles at 100 mA g−1 for MnO2, Mn3O4 and MnO. Even at 500 mA g−1, the reversible capacities could be still kept at 637, 820, and 1050 mA h g−1 after 150 cycles. The outstanding performances might be related with their hollow structure, porous surface and nanoscale size.

Surface-Amorphous and Oxygen-Deficient Li3VO4-δ as a Promising Anode Material for Lithium-Ion Batteries.

Surface‐amorphous and oxygen‐deficient Li3VO4−δ synthesized by simple annealing of Li3VO4 powders in a vacuum shows great enhancements in both reversible capacity and coulombic efficiency for the first discharge/charge without delicate size control and carbon coating. The results are associated with the improved charge‐transfer kinetics caused by the amorphous surface of Li3VO4−δ.

Synthesis of novel morphologies of Li2FeSiO4/C micro/nano composites by a facile hydrothermal method

Carambola and jujube-seed-shaped Li2FeSiO4 assembled by nanoplates have been successfully synthesized by a simple hydrothermal method. The different morphologies are induced by two different iron precursors, which affect the self-organization behaviour of primary particles of Li2FeSiO4. The electrochemical performances of the two Li2FeSiO4/C composites are also influenced by the different morphology.

Design and synthesis of a stable-performance P2-type layered cathode material for sodium ion batteries

P2-type Na0.6Ni0.2Co0.2Mn0.5Ti0.1O2 powders are successfully synthesized by a solid state reaction. Ex situ XRD reveals the phase transition process from P2 to O2 occurs at 4.1 V. As they are cycled in a narrow voltage window (4.2–2 V), they exhibit excellent cycling stability and high rate capability. Even at 5C for 250 cycles, the reversible capacity could be kept at 66.0 mA h g−1.

Tunnel-structured Na(0.54)Mn(0.50)Ti(0.51)O2 and Na(0.54)Mn(0.50)Ti(0.51)O2/C nanorods as advanced cathode materials for sodium-ion batteries.

Tunnel-structured Na(0.54)Mn(0.50)Ti(0.51)O2 nanorods have been synthesized by a facile molten salt method. These nanorods are grown in the direction normal to the sodium-ion tunnels, greatly shortening the diffusion distance of sodium ions and benefiting the transfer kinetics. Thus, the nanorods show significant enhancements in terms of reversible capacity, cycling stability and rate capability. The electrochemical performance could be further promoted via carbon coating to ∼122 mA h g(-1) after 150 cycles at 0.2 C or ∼85 mA h g(-1) after 400 cycles at 1 C.