Dingtao Ma

Li1.2Mn0.54Ni0.13Co0.13O2-Encapsulated Carbon Nanofiber Network Cathodes with Improved Stability and Rate Capability for Li-Ion Batteries.

Li1.2Mn0.54Ni0.13Co0.13O2-encapsulated carbon nanofiber network cathode materials were synthesized by a facile electrospinning method. The microstructures, morphologies and electrochemical properties are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), galvonostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy (EIS), etc. The nanofiber decorated Li1.2Mn0.54Ni0.13Co0.13O2 electrode demonstrated higher coulombic efficiency of 83.5%, and discharge capacity of 263.7 mAh g−1 at 1 C as well as higher stability compared to the pristine particle counterpart. The superior electrochemical performance results from the novel network structure which provides fast transport channels for electrons and lithium ions and the outer carbon acts a protection layer which prevents the inner oxides from reacting with HF in the electrolyte during charge-discharge cycling.

Oxygen Vacancy Engineering in Tin(IV) Oxide Based Anode Materials toward Advanced Sodium-Ion Batteries

A high theoretical capacity of approximately 1400 mA h g-1 makes SnO2 a promising anode material for sodium-ion batteries (SIBs). However, large volume expansion, poor intrinsic conductivity, and sluggish reaction kinetics have greatly hindered its practical application. The controlled creation of oxygen vacancy (OV) defects allows the intrinsic properties of SnO2 to be effectively modulated, but related work concerning SIBs is still lacking. In this Minireview, the mechanism of failure of SnO2 electrodes is discussed and an overview of recent progress in the general synthesis of OV-containing SnO2 materials and the feasible detection of OVs in SnO2 is presented. The use of OV-containing SnO2 -based anode materials in SIBs is also reviewed. Finally, challenges and future opportunities to engineer OVs for semiconductor oxides are examined.