Mechanism of action of ethylene sulfite and vinylene carbonate electrolyte additives in LiNi1/3Mn1/3Co1/3O2/graphite pouch cells: electrochemical, GC-MS and XPS analysis.

The role of ethylene sulfite used either alone or in combination with VC in LiNi1/3Mn1/3Co1/3O2 (NMC)/graphite pouch cells was studied by correlating data from differential capacity (dQ/dV) analysis, gas chromatography/mass spectroscopy (GC-MS), theoretical calculations, ultrahigh precision coulometry, storage experiments and X-ray photoelectron spectroscopy. For cells containing VC alone, the electrochemical performance and gas production were greatly improved, compared to cells without VC, due to the formation of more stable and protective SEI films at both electrode surfaces by a polymer of VC. For cells with ES alone, a vigorous reactivity was observed due to preferential reduction that also generated large amounts of gas during formation. The dramatic decrease in electrochemical performance as well as the continuous production of gas during cycling in cells with ES was explained by the formation of a very thin and ineffective SEI film at the NMC surface. The suppression of the vigorous reaction of ES in cells with both ES and VC occurred because the solvation energy of Li(+) by VC is smaller than that of EC so VC is reduced first during formation. During charge-discharge cycling, a slow consumption of ES occurred and different sulfur species were observed on the electrodes when VC was combined with ES. SEI film formation processes and SEI composition were therefore dominated by VC and the electrochemical performance of cells with both VC and ES were similar compared to those of cells with VC alone.

Evaluation of the SO(2) and NH(3) gas adsorption properties of CuO/ZnO/Mn(3)O(4) and CuO/ZnO/NiO ternary impregnated activated carbon using combinatorial materials science methods.

Impregnated activated carbons (IAC) are widely used materials for the removal of toxic gases in personal respiratory protection applications. The combinatorial method has been employed to prepare IACs containing different types of metal oxides in various proportions and evaluate their adsorption performance for low molecular weight gases, such as SO(2) and NH(3), under dry conditions. Among the metal oxides used for the study, Mn(3)O(4) was found to have the highest capacity for retaining SO(2) gas under dry conditions. NiO and ZnO were found to have similar NH(3) adsorption capacities which are higher than the NH(3) capacities observed for the other metal oxide impregnants used in the study. Although Cu- or Zn-based impregnants and their combinations have been extensively studied and used as gas adsorbents, neither Mn(3)O(4) nor NiO have been incorporated in the formulations used. In this study, ternary libraries of IACs with various combinations of CuO/ZnO/Mn(3)O(4) and CuO/ZnO/NiO were studied and evaluated for their adsorption of SO(2) and NH(3) gases. Combinations of CuO, ZnO, and Mn(3)O(4) were found to have the potential to be multigas adsorbents compared to formulations that contain NiO.

SO2 and NH3 gas adsorption on a ternary ZnO/CuO/CuCl2 impregnated activated carbon evaluated using combinatorial methods.

Ternary libraries of 64 ZnO/CuO/CuCl(2) impregnated activated carbon samples were prepared on untreated or HNO(3)-treated carbon and evaluated for their SO(2) and NH(3) gas adsorption properties gravimetrically using a combinatorial method. CuCl(2) is shown to be a viable substitute for HNO(3) and some compositions of ternary ZnO/CuO/CuCl(2) impregnated carbon samples prepared on untreated carbon provided comparable SO(2) and NH(3) gas removal capacities to the materials prepared on HNO(3)-treated carbon. Through combinatorial methods, it was determined that the use of HNO(3) in this multigas adsorbent formulation can be avoided.