Influence of carbon towards improved lithium storage properties of Li2MnSiO4 cathodes

Abstract

Superior lithium storage in Li2MnSiO4 cathodes was observed by altering carbon content during the formulation of electrodes. Initially, Li2MnSiO4 was prepared by a conventional solid-state reaction at 900 °C under Ar flow with a fixed amount of adipic acid, which acts as a gelating agent during synthesis. The phase formation was confirmed through powder X-ray diffraction measurements. Scanning electron microscope pictures indicate the particulate morphology of synthesized Li2MnSiO4 particles. Various compositions of electrodes were formulated using the conducting carbon (ketjen black) from 3 to 11 mg along with active material. All the fabricated electrodes were cycled in a Li/Li2MnSiO4 cell configuration to evaluate its lithium storage performance at 0.05 C rate. Among the electrodes, 42% carbon in the composite electrode exhibited a very stable discharge behaviour ∼140 mA h g−1 for 40 cycles at room temperature. Such storage performance was ascribed to the improved electronic conductivity of Li2MnSiO4 electrodes by incorporating carbon. This improvement was supported by electrochemical impedance spectroscopy measurements. Rate performance studies were also conducted and presented in the manuscript.