In this study spinel‐lithium manganese oxide (LiMn2O4) powders were prepared by using a simple sol–gel method with polyvinyl alcohol (PVA), and further combined with a conductive additive, graphene, to produce a composite electrode material for improved performance. The effects of the variation in the ratios of binder (PVA) to LiMn2O4 precursor on the particle size and electrochemical behavior of the composite were studied. Particle sizes of <200 nm were obtained. An energy density of 17.36 Wh kg−1 was obtained at an operating voltage of 3.2 V for the pure LiMn2O4 sample tested against a graphene electrode. For simultaneously improving power density (current Li batteries have a low power density as a disadvantage) along with energy density, the LiMn2O4–graphene composite was chosen as an electrode material. LiMn2O4–graphene composite electrodes were prepared by electrophoretic co‐deposition. The ratio of LiMn2O4–graphene composite was optimized to 1:1 during the electrode study based on its electrochemical performance. An average energy density of 30 Wh kg−1, a specific capacity of 49 mAh g−1, and an enhanced power density of 800 W kg−1 at a discharge current of 0.5 A g−1 were obtained. Discharge behavior improved evidently for tests performed on composite electrodes with increased LiMn2O4 (1:1.3 graphene/LiMn2O4). An improved average energy density of 59.6 Wh kg−1 was obtained along with a power density of 697 W kg−1. The electrodes showed good performance during study of a button cell device. Such electrodes are well suited for hybrid energy storage devices having good energy and power density and bridging the gap between batteries and supercapacitors.

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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.

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