caused by slow oxidation of the electrolyte by the fully charged manganese oxide, corrosion at the current collector interfaces, and/ or mass transfer effects. These phenomena can easily be minimized by lowering the voltage limit upon charge, improving electrolyte compositions and current collector materials, and by judicious use of rest periods between half-cycles. At any rate, these early results demonstrate that the orthorhombic sodium manganese oxide is remarkably stable and undergoes alkali metal intercalation processes readily and reversibly. Conclusions The suitability of the orthorhombic sodium manganese oxide for use as a cathode material in alkali metal secondary batteries has been demonstrated. This material, which has never before been used in a battery, has high specific capacity in both lithium and sodium cells, and discharge characteristics suitable for use with polymer electrolytes. An especially striking feature is the excellent reversibility and stability upon cycling in lithium cells.

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SYNOPSISA method based on the use of 13C NMR relative peak intensity ratios for different characteristic chemical groups, known or supposed to contribute to urea-formaldehyde ( UF ) resin strength and formaldehyde emission is presented. The method relates results obtained by 13C NMR analysis of liquid UF resins with their strength, formaldehyde emission, and percent crystallinity in the resin-hardened state. Correlation of different peak ratios with experimental results allows the proposal of equations relating the sum of a number of different 13C NMR peak ratios with the three mentioned physical properties of the same resins in their hardened state. Resin strength and percent crystallinity appear to be loosely, inversely related. The equations presented appear to have some applied value in predicting physical properties of hardened industrial-type UF resins from a single 13C NMR spectrum of the original liquid resins, as well as to render easier comparison between difficult UF resin formulations. This approach has allowed identification of which chemical groups really contribute to the physical properties of the hardened resin, and to what extent.

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Incremental capacity analysis (ICA) has proven to be an effective tool for determining the state of health (SOH) of Li-ion cells under laboratory conditions. This paper deals with an outstanding challenge of applying ICA in practice: the evaluation of battery series connections. The study uses experimental aging and characterization data of lithium iron phosphate (LFP) cells down to 53% SOH. The evaluability of battery series connections using ICA is confirmed by analytical and experimental considerations for cells of the same SOH. For cells of different SOH, a method for identifying non-uniform aging states on the modules’ IC curve is presented. The findings enable the classification of battery modules with series and parallel connections based on partial terminal data.

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