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Zinc metal is widely used as an anode in various aqueous systems. However, zinc anode suffers from the dendrite formation on the surface upon cycling leading to a poor cyclability of a cell and its termination due to short circuit. In this work, the effect of tetrapropylammonium hydroxide (TPAH) was studied as an electrolyte additive for aqueous Zn//ZnCl2 + LiCl//LiFePO4 battery. TPAH additive prolongs the battery cycle life depending on its concentration (0.01–0.1 M). The better capacity retention over 350 cycles was observed for a symmetrical Zn//ZnCl2 + LiCl//Zn cell with 0.05 M TPAH whereas without additives the cell worked for only 110 cycles. The mechanism of TPAH influence on capacity retention is proposed based on the results of SEM and XRD analysis of the Zn anode and FTIR and NMR studies of the electrolyte. The XRD patterns of the negative electrode of the cell with TPAH indicates that zinc was preferentially deposited in a highly oriented (002) direction, which is more resistant against dendrite formation. These differences in deposited structure of Zn dendrites were confirmed by SEM images as well. FTIR and NMR spectra showed that TPAH decomposes to propylamine (RnN+H) and propene during cycling. TPAH also has an effect on the size and uniform distribution of Zn growth sides.

The possibility of removing Cu 2+ and Pb 2+ ions from solutions by the yeast cells Rhodotorula glutinis and diatomite (natural mineral) was studied. It is shown that at the concentration of CuSO 4 and Pb(NO 3 ) 2 10 -3 mol/l the removal of metal ions by yeast cells was 59.1 and 72.4% for the ions of Cu 2+ and Pb 2+. The yeast cells surface includes amino, hydroxyl, phosphate and carboxyl groups which activates sorption ability, because these groups can bind metal ions by ion exchange, donor acceptor and electrostatic interactions. The removal degree of metal ions by diatomite under the same conditions was for Cu 2+ 91.6% and for Pb 2+ 94.7%. To increase the removal degree of metal ions from solutions, the yeast cells were immobilized on the surface of diatomite. In order to attach the negatively charged cells of microorganisms with negatively charged surface of the mineral, the surface of diatomite was modified by polyethylenimine (PEI). As a result, the immobilization degree of Rhodotorula glutinis to the surface of diatomite at the concentration of PEI 0.02 base-mol/l increased from 62 to 88%, which is explained by the existence of electrostatic contacts between the negatively charged functional groups of the cell surface and amino groups of PEI, that has covered the surface of diatomite by PEI. It is shown that the obtained composite biosorbent removes 97.8% of Cu 2+ ions and 99.4% of Pb 2+ ions.

Non-flammable, high durability and low cost battery is required for smart grids applications. Zinc-based rechargeable batteries such as zinc–nickel oxide systems are one of the most attractive energy storage systems for such applications due to the advantages of zinc as low cost, abundance, and low toxicity. Higher energy density in terms of both weight (Whkg− 1) and volume (WhL− 1) is also expected compared with conventional batteries such as nickel–metal hydride [1]. The primary issue limiting use of zinc anodes in rechargeable batteries is the short cycle life caused by dendrite formation upon cycling causing short circuiting [2,3]. In order to solve this problem flow-assisted Zn/NiOOH batteries have been suggested, but this battery needs flowing KOH aqueous electrolyte solution to suppress Zn whisker growth [4].   In current work, a novel flow-assist free battery was developed to meet the requirements for above mentioned applications. This battery was prepared by electrodeposition of NiOOH cathode and anode, and using an aqueous electrolyte. Electrodeposition is one of the most economical and facile technique for producing metal/hydroxide electrodes, which used in this work to prepare both NiOOH and Zn electrodes. The electrodes were directly electrodeposited onto three-dimensional carbon fiber paper (CFP) substrates. Both electrodeposited electrodes were characterized by scanning electron microscopy (SEM, Fig. 1) and X-ray diffraction (XRD) which confirmed formation of NiOOH and Zn, respectively.   Galvanostatic charge-discharge tests conducted at 0.05 C rate showed that the prepared NiOOH cathode delivers a discharge capacity of 250 mAh/g when used with the electrodeposited Zn anode. Further details of the work will be presented at the meeting. Acknowledgements This work was supported under the Technology Commercialization Project (Grant # OK_653) supported by the World Bank and the Government of the Republic of Kazakhstan, and a research Grant #3756/GF4 from the Ministry of Education and Science of Kazakhstan. References [1]Y. Ito, M. Nyce, R. Plivelich, M. Klein, D. Steingart, S. Banerjee J. of Power Sources 196 (2011) 2340 [2] R.D. Naybour, J. Electrochem. Soc. 116 (1969) 520. [3] R.Y. Wang, D.W. Kirk, G.X. Zhang, J. Electrochem. Soc. 153 (2006) C357.[4] G. Bronoel, A. Millot, N. Tassin, J. Power Sources 34 (1991) 243. Figure 1

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