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As interest in electric vehicles and mass energy storage systems continues to grow, Li-O batteries are attracting much attention as a candidate for next-generation energy storage systems owing to their high energy density. However, safety problems related to the use of lithium metal anodes have hampered the commercialization of Li-O batteries. Herein, we introduced a quasi-solid polymer electrolyte with excellent electrochemical, chemical, and thermal stabilities into Li-O batteries. The ion-conducting QSPE was prepared by gelling a polymer network matrix consisting of poly(ethylene glycol) methyl ether methacrylate, methacrylated tannic acid, lithium trifluoromethanesulfonate, and nanofumed silica with a small amount of liquid electrolyte. The quasi-solid-state Li-O cell consisted of a lithium powder anode, a quasi-solid polymer electrolyte, and a PdCo/multiwalled carbon nanotube cathode, which enhanced the electrochemical performance of the cell. This cell, which exhibited improved safety owing to the suppression of lithium dendrite growth, achieved a lifetime of 125 cycles at room temperature. These results show that the introduction of a quasi-solid electrolyte is a potentially new alternative for the commercialization of solid-state Li-O batteries.

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Tungsten (W) was coated onto a silicon (Si) anode at the nanoscale via the physical vaporization deposition method (PVD) to enhance its electrochemical properties. The characteristics of the electrode were identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis, and electron probe X-ray microanalysis. With the electrochemical property analysis, the first charge capacities of the W-coated and uncoated electrode cells were 2558 mAh g− 1 and 1912 mAh g− 1, respectively. By the 50th cycle, the capacity ratios were 61.1 and 25.5%, respectively. Morphology changes in the W-coated Si anode during cycling were observed using SEM and TEM, and electrochemical characteristics were examined through impedance analysis. Owing to its conductivity and mechanical properties from the atomic W layer coating through PVD, the electrode improved its cyclability and preserved its structure from volumetric demolition.

A lithium powder electrode is applied as an anode in a lithium-sulfur battery system to examine the effects of changes in the anode surface area on electrochemical behavior. Besides preventing dendrite growth, as in other lithium-ion batteries, the lithium powder anode achieves an elevation in lithium-ion transfer, which can be attributed to an increase in the exchange current density caused by expansion of the surface area of the anode. This promotion of lithium-ion diffusion also leads to an increase in lithium-ion transfer near the cathode site and contributes to the reversible reaction between the lithium ion and sulfur. As a result, the reversibility in cathodic reactions is enhanced, thereby improving its specific capacity and retention. Scanning electron microscopy and X-ray photoelectron spectroscopy reveal that the morphology of the cathode is maintained throughout the process, and a solid electrolyte interphase (SEI) with lower electrolyte decomposition can be constructed. Impedance analysis also confirms that a stable electrochemical reaction is achieved with low resistance values.