Guobiao Liu

High performance NiO nanosheets anchored on three-dimensional nitrogen-doped carbon nanotubes as a binder-free anode for lithium ion batteries

Transition metal oxides (TMOs) have attracted extensive research attention as promising anode materials for lithium ion batteries due to their high theoretical capacities. However, their applications have been hindered by their poor electronic conductivity and drastic volume change in the reversible conversion reaction. Here three-dimensional NiO ultrathin nanosheets were grown on the composites of N-doped carbon nanotubes (N-CNTs) and Ni foam by chemical vapor deposition and electrochemical deposition methods, and the 3D Ni foam/N-CNT/NiO nanosheet electrode thus obtained exhibits larger capacity, better cycling stability, superior rate capability and higher ionic conductivity. The first-principles calculations suggest that N-doping can improve the interaction between NiO and N-CNTs, which can facilitate fast electron hopping from N-CNTs to NiO to enhance the electronic conductivity. The results indicate that the introduction of N-doped carbon nanotubes can greatly improve the electrochemical performance of NiO. The understanding between N-CNTs and NiO can be extended to the preparation of N-CNTs coated with other high-performance electrode materials for energy-storage devices.

Hierarchical LiNi0.8Co0.15Al0.05O2 plates with exposed {010} active planes as a high performance cathode material for Li-ion batteries

Exposed {010} active planes can provide more tunnels for Li+ insertion/extraction through the particle surface. In this work, hierarchical LiNi0.8Co0.15Al0.05O2 plates with exposed {010} active planes were successfully obtained via a solvothermal method followed by solid-state reaction. The as-synthesized hierarchical LiNi0.8Co0.15Al0.05O2 plates demonstrate a superior rate capability.

Hollow Li1.2Mn0.54Ni0.13Co0.13O2 micro-spheres synthesized by a co-precipitation method as a high-performance cathode material for Li-ion batteries

Hollow Li1.2Mn0.54Ni0.13Co0.13O2 micro-spheres were successfully synthesized by a co-precipitation method. The micro-spheres deliver an initial discharge capacity of 296 mA h g−1 and a coulombic efficiency of 83.4% at a current density of 30 mA g−1. Furthermore, the micro-spheres exhibit an excellent rate capability (150 mA h g−1 at a current density of 1500 mA g−1) and a high reversible discharge capacity of 227 mA h g−1 after 100 cycles at a current density of 60 mA g−1.

Effect of Na 2 S treatment on the structural and electrochemical properties of Li 1 . 2 Mn 0 . 54 Ni 0 . 13 Co 0 . 13 O 2 cathode material

The electrochemical performances of Li1.2Mn0.54Ni0.13Co0.13O2 cathode material are enhanced through hydrothermal approach using Na2S solution as a medium. Furthermore, the influence of contents of Na2S solution on the morphology, structure, and electrochemical performances is fully investigated. The results indicate that a high content of Na2S solution results in the formation of spinel particles which are detected by SEM, XRD, and HR-TEM measurements. The formation of spinel particles leads to a deterioration of electrochemical performances. However, a low content of Na2S solution results in a slight structure change from layered phase to spinel one near the edge of Li1.2Mn0.54Ni0.13Co0.13O2 particles. This slight structure change facilitates the decrease of charge transfer resistance, which contributes to the enhanced rate capability of Na2S-treated Li1.2Mn0.54Ni0.13Co0.13O2.

Robust Succinonitrile-Based Gel Polymer Electrolyte for Lithium-Ion Batteries Withstanding Mechanical Folding and High Temperature

Fabrication of a gel polymer electrolyte containing succinonitrile (GPE-SN) with high mechanical strength is quite challenging because the SN electrolyte always suppresses the formation of polymer networks during in situ polymerization. In this work, a mechanically robust GPE-SN was successfully prepared by using a solution immersion method. During fabrication, the paste-like SN electrolyte was transformed into a liquid SN electrolyte with low viscosity by heating at 50 °C and then infiltrated into the UV-cured highly cross-linked polyurethane acrylate (PUA) skeleton. The resulted GPE-SN film exhibits superior tensile strength (6.5 MPa) compared to the one (0.5 MPa) prepared by in situ polymerization (GPE-SN-IN). The high mechanical strength of the GPE-SN-IM film enables the LiCoO2/Li4Ti5O12 film battery to withstand 100-cycle folding without electrolyte damage and capacity loss. Besides, the GPE-SN presents a high ionic conductivity (1.63 × 10-3 S·cm-1 at 25 °C), which is comparable to GPE with a commercial liquid electrolyte (GPE-LE). Because of good thermal stability of the GPE-SN, the LiCoO2/Li cell with this electrolyte shows better charge-discharge cycling stability than that with GPE-LE at high temperature (55 °C). Thus, the GPE-SN prepared by our method could be a promising polymer electrolyte offering better safety and reliability for lithium-ion batteries.