Xiuwan Li

Nanostructured NiO electrode for high rate Li-ion batteries

A simple thermal oxidation approach has been used to fabricate nanostructured NiO electrodes at a temperature as low as 400 °C in air. Galvanostatic battery testing showed that the NiO electrode exhibits excellent rate capability and high capacity. The performances can be attributed to its favorable morphology and the better electrical contact between NiO and Ni.

Germanium Anode with Excellent Lithium Storage Performance in a Germanium/Lithium–Cobalt Oxide Lithium-Ion Battery

Germanium is a highly promising anode material for lithium-ion batteries as a consequence of its large theoretical specific capacity, good electrical conductivity, and fast lithium ion diffusivity. In this work, Co3O4 nanowire array fabricated on nickel foam was designed as a nanostructured current collector for Ge anode. By limiting the voltage cutoff window in an appropriate range, the obtained Ge anode exhibits excellent lithium storage performance in half- and full-cells, which can be mainly attributed to the designed nanostructured current collector with good conductivity, enough buffering space for the volume change, and shortened ionic transport length. More importantly, the assembled Ge/LiCoO2 full-cell shows a high energy density of 475 Wh/kg and a high power density of 6587 W/kg. A high capacity of 1184 mA h g(-1) for Ge anode was maintained at a current density of 5000 mA g(-1) after 150 cycles.

Self-supporting Co3O4 with lemongrass-like morphology as a high-performance anode material for lithium ion batteries

Self-supporting Co3O4 with lemongrass-like morphology exhibits excellent rate capability and cyclic stability for high-performance Li ion batteries as electrodes. It retains a high reversible capacity of up to 981 mA h g−1 after 100 cycles at a rate of 0.5 C and a capacity higher than 381 mA h g−1 even at a rate as high as 10 C.

Carbon-Wrapped Fe3O4 Nanoparticle Films Grown on Nickel Foam as Binder-Free Anodes for High-Rate and Long-Life Lithium Storage

Carbon-wrapped Fe3O4 nanoparticle films on nickel foam were simply prepared by a hydrothermal synthesis with sucrose as a precursor of subsequent carbonization. The as-prepared samples were directly used as binder-free anodes for lithium-ion batteries which exhibited enhanced rate performance and excellent cyclability. A reversible capacity of 543 mA h g(-1) was delivered at a current density as high as 10 C after more than 2000 cycles. The superior electrochemical performance can be attributed to the formation of a thin carbon layer which constructs a 3D network structure enwrapping the nanosized Fe3O4 particles. Such an architecture can facilitate the electron transfer and accommodate the volume change of the active materials during discharge/charge cycling.

Facile preparation of Mn3O4-coated carbon nanofibers on copper foam as a high-capacity and long-life anode for lithium-ion batteries

Carbon nanofibers (CNFs) were deposited on Cu foam by a floating catalyst method, and a Mn3O4 layer was then coated onto the deposited CNFs via a hydrothermal process based on the redox reaction of carbon and potassium permanganate. The obtained architecture of Mn3O4-coated CNFs (CNFs@Mn3O4) on Cu foam was directly used as an anode for lithium-ion batteries without using any binder or conducting additive. The anode showed high reversible capacity, good cycle stability and superior rate capability. A reversible capacity of up to 1210.4 mA h g(-1) was obtained after 50 cycles at a current density of 100 mA g(-1). When the current density increased to 5000 mA g(-1), it could deliver a capacity of more than 300 mA h g(-1). The excellent electrochemical performance could be attributed to the unique morphology of the CNFs@Mn3O4 nanocomposites, which can buffer the volume change, decrease the contact resistance, shorten the ionic diffusion path and make the electron transport more efficient.

Group IVA Element (Si, Ge, Sn)-Based Alloying/Dealloying Anodes as Negative Electrodes for Full-Cell Lithium-Ion Batteries

To satisfy the increasing energy demands of portable electronics, electric vehicles, and miniaturized energy storage devices, improvements to lithium-ion batteries (LIBs) are required to provide higher energy/power densities and longer cycle lives. Group IVA element (Si, Ge, Sn)-based alloying/dealloying anodes are promising candidates for use as electrodes in next-generation LIBs owing to their extremely high gravimetric and volumetric capacities, low working voltages, and natural abundances. However, due to the violent volume changes that occur during lithium-ion insertion/extraction and the formation of an unstable solid electrolyte interface, the use of Group IVA element-based anodes in commercial LIBs is still a great challenge. Evaluating the electrochemical performance of an anode in a full-cell configuration is a key step in investigating the possible application of the active material in LIBs. In this regard, the recent progress and important approaches to overcoming and alleviating the drawbacks of Group IVA element-based anode materials are reviewed, such as the severe volume variations during cycling and the relatively brittle electrode/electrolyte interface in full-cell LIBs. Finally, perspectives and future challenges in achieving the practical application of Group IVA element-based anodes in high-energy and high-power-density LIB systems are proposed.

A facile and inexpensive approach to improve the performance of silicon film as an anode for lithium-ion batteries

Silicon is considered as a promising candidate for next-generation lithium-ion battery anodes. However, severe capacity fading caused by volume change during Li-ion insertion and extraction hinders its practical application. In this work, gold granular film and polyvinylidene fluoride coating are sequentially prepared on the deposited Si film to solve the aforementioned problem.

In situ coating of NiO on Ni-silicide nanowires with roughened surfaces for improved electrochemical energy storage

NiO layers were coated in situ onto Ni-silicide nanowires by an oxidation in air. The surface of the nanowires had been previously roughened by etching in HF solution. It is found that the roughened surface is very helpful to enhance the in situ coating ability of NiO on the nanowires. When the resulting samples were used as anodes for lithium-ion batteries, a high reversible capacity of 1.28 mA h cm−2 was obtained for the surface-roughened nanowires with 30 min HF-treatment, which is 3 times higher than that of the nanowires without HF-treatment. The current density can reach up to 2.15 mA cm−2 for the 60 min HF-treated and then oxidized nanowires, while the capacity is maintained at as high as 0.52 mA h cm−2. The improved cyclic performance could be attributed to the roughened surface of the nanowires, which enhanced the coating ability of the NiO layers, and provided a porous structure that is of benefit to increase the area of the electrode/electrolyte interface for the adsorption of ions. In addition, the Ni-silicide nanowires can improve the electrode conductivity and act as a stable support for the NiO coating layers during cycling, making a positive contribution to the electrochemical performance.