Understanding the behavior of lithium plating at low temperatures is crucial for optimizing charging protocols, and assuring safe and durable use of lithium-ion batteries. In this work, the electrochemical model with lithium plating as the side reaction is adopted to explore the phenomena and mechanisms. The model is parameterized and validated through the measured OCV (open circuit voltage), the discharging curves at different C-rates and temperatures, and especially the amount of plated metallic lithium under various conditions detected with NMR (nuclear magnetic resonance). When a coin model cell is charged from 0% to 60% (−25 • C), 80% (−25 • C), and 80% SOC (−20 • C) using 1.5 C current, the lithium plating ratios, defined as the ratio between the charge corresponding to lithium plating and the total charge, are 1.15%, 1.55% and 0.92% respectively. The model indicates that lithium plating could occur even at SOCs lower than 10%, before the lithium-ion concentration at the surface of graphite particles becomes saturated. This can be attributed to the larger activation energy of lithium-ion intercalation, compared to that of lithium plating, which reduces the surface potential below the plating potential. The model is also used to determine the operating limits and subsequently the fast and safe charging protocols.

The correlation between the degradation behavior of a membrane electrode assembly ͑MEA͒ and deposited Pt ͑Pt band͒ in the membrane during an open-circuit voltage hold test was studied. The degradation behavior was investigated by measuring the fluoride ion emission in the effluent water from the anode and the cathode for various gas compositions at both electrodes. The results showed that the fluoride ion emission rate ͑FER͒ varied in accordance with the gas compositions. Cross sections of the tested MEAs were observed using a transmission electron microscope. It was found that the location of the Pt band correlated with the magnitude of the FERs. The Pt band was located close to where the mixed potential in the membrane, which was determined by the gas compositions, changed dramatically.

The correlation between the degradation behavior of a membrane electrode assembly (MEA) and deposited Pt (Pt band) in the membrane during an open circuit voltage (OCV) hold test was studied. It was found that the location of the Pt band correlated with the magnitude of the FERRs. The Pt band was observed close to where the mixed potential in the membrane, which was determined by the gas compositions, changed dramatically.

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The Arbuzov reaction of (2S,4S)-4-methyl-2-phenyl-1,3,2-dioxaphosphorinane with various alkyl halides gave the diastereomerically pure phosphinates with regioselective cleavage of the primary carbon–oxygen bond. These phosphinates reacted with Grignard reagents to give optically active phosphine oxides in high optical yields.