Lithium-ion batteries (LIBs) are ubiquitously used in portable and telecommunication electronic devices and are also promising for electric vehicles and electric grid applications. In LIBs, a good cathode material should ideally have a high Li intercalation voltage while a good anode material should have low Li de-intercalation voltage. Recently, composite cathode materials with Li2MnO3–stabilized LiMO2 (M = Mn, Ni, and Co) were introduced, which have high potential (&gt; 4.3 V vs. Li+/Li) and superior capacities and merit further research. Their charge storage capabilities can reach up to 300 mAh/g, limited by topotactic reaction at the electrodes. This layered-layered cathode structure has been proven to be a viable option to achieve higher capacities (&gt;200 mAh g-1) and to operate at a higher voltage above 4.3 V vs. Li/Li+. However, serious structural stability and manganese dissolution issues during repeated charge-discharge cycling reduce capacity considerably. Subsequent theoretical and experimental studies revealed that composite layered-layered cathode performance is highly dependent upon composition, synthesis conditions (temperature, pH, etc.), and particle size. In this research, we add a spinel component, e.g. LiNi0.5Mn1.5O4, to the above layered-layered composite cathode allowing fast Li+ diffusion and to operate even at a higher voltages (&gt;4.7 V vs. Li/Li+) with better structural stability over the repeated cycling. Here, we control precisely the mole ratio of C2/m Li2MnO3, R-3m Li1.2Mn0.56Ni0.12Co0.12O2, and Fd-3m LiNi0.5Mn1.5O4 to form a closely-connected “layered-layered-spinel” composite cathode using an efficient coprecipitation and hydrothermal route. X-ray diffraction, scanning electron microscopy, Raman spectroscopy were used in conjunction with standard electrochemical techniques (cyclic voltammetry, chronopotentiometry) for characterizing the electrode materials.

Synthesis and characterization of an improved nanocomposite cathode materials for Li-ion batteries

2019 Spring National Meeting

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