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This report unravels the dependence of the microstructure and electrochemical performances of Li-rich layered transition metal oxide (LLMO) on the molecular structure of polymer templates for the formation of oxalate precursor. A representative LLMO, Li1.2Mn0.54Ni0.13Co0.13, is synthesized by co-precipitation method, and three samples, LLMO-PVP, LLMO-PEG and LLMO-PVA, are obtained with polymer templates, polyvinyl pyrrolidone (PVP), polyethyleneglycol (PEG) and polyvinyl alcohol (PVA), respectively. The physical and chemical properties of the resulting products are analyzed with SEM, TEM, XRD, BET, ICP, and XPS, and their electrochemical performances as cathode of Li-ion battery are evaluated with EIS, GITT and charge/discharge tests. It is found that LLMO-PVP exhibits the best performances, followed by LLMO-PEG, while LLMO-PVA behaves poorest. This difference is ascribed to the various microstructures of the resulting products, which are determined by the molecular structure of polymer templates.

A novel electrolyte additive 3-sulfolene (3SF) for graphite anode is proposed in this work according to the DFT calculation. The calculated electron affinity energy of the investigated solvents and additives reveals that 3SF shows the highest reductive activity, which is further confirmed by the cyclic voltammetry test. The characterization results from charge/discharge cycle, scanning electron microscope, transmission electron microscope and elemental mapping demonstrate that the preferential reduction of 3 wt% 3SF additive generates a thin and uniform SEI film on the graphite surface, which effectively suppresses the continuous co-insertion and reduction of PC-based electrolyte, resulting in high cyclic stability of Li/graphite cell in PC-based electrolyte. Importantly, the ability of 3SF on improving the interfacial stability of graphite/PC-based electrolyte is better than that of the prop-1-ene-1,3-sultone which is believed to be the most promising candidates to alternate vinylene carbonate.