Electrochemical Performance of Electrophoretically Deposited Nanostructured LiMnPO4-Sucrose Derived Carbon Composite Electrodes for Lithium Ion Batteries.

The present study reports an approach by which thin films of sucrose added olivine type LiMnPO4-Ccomposite and pristine LiMnPO4 is made by a technique of electrophoretic co-deposition in which pristine and composite samples were synthesized by a sol-gel route. These thin films with enhanced surface area is used to fabricate cathodes for rechargeable Li ion batteries. XRD confirms phase pure single crystalline orthorhombic structure. Transmission Electron Microscopy (TEM) images shows the carbon coating over LiMnPO4 and the particle size restricted in the nano regime. The presence of sp2 hybridized carbon on LiMnPO4 particles is confirmed by X-ray Photon spectroscopy (XPS). To explore the electrochemical behavior, cyclic voltammetry (CV) and cycling studies were performed. The specific capacity for LiMnPO4-C is found to be increased by 43% in comparison to the pristine LiMnPO4. It also exhibited 86% retention in capacity compared to the pristine LiMnPO4 (52%). The result indicates that a proper carbon coating can significantly improve the electronic conductivity and hence the specific capacity.

Thin film rechargeable electrodes based on conductive blends of nanostructured olivine LiFePO4 and sucrose derived nanocarbons for lithium ion batteries.

The present study provides the first reports of a novel approach of electrophoretic co-deposition technique by which titanium foils are coated with LiFePO4-carbon nanocomposites synthesized by sol gel route and processed into high-surface area cathodes for lithium ion batteries. The study elucidates how sucrose additions as carbon source can affect the surface morphology and the redox reaction behaviors underlying these cathodes and thereby enhance the battery performance. The phase and morphological analysis were done using XRD and XPS where the LiFePO4 formed was confirmed to be a high purity orthorhombic system. From the analysis of the relevant electrochemical parameters using cyclic voltammetry and electrochemical impedance spectroscopy, a 20% increment and 90% decrement in capacity and impedance values were observed respectively. The composite electrodes also exhibited a specific capacity of 130 mA h/g. It has been shown that cathodes based on such composite systems can allow significant room for improvement in the cycling performance at the electrode/electrolyte interface.