Laser Raman spectroscopy study of the zinc and bromide ion complex equilibrium in zinc/bromine battery electrolytes. [2M ZnBr/sub 2/ and 1M KBr solution]

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5622754

Grimes, P G; Larrabee, J A

Laser Raman spectroscopy was used to study the zinc and bromide ion complex equilibrium in zinc bromine battery model electrolytes. Solutions of zinc bromide with added KBr, HBr and N-methyl, N-ethyl morpholinium (MEM) bromide were examined and compared. Solutions studied ranged from 1 to 3 molar in zinc and from 2.5 to 8 molar in bromide. A typical Raman spectrum of a zinc bromide solution is shown in Figure 1. Each of the zinc species is identified, Zn/sup + +/ (aq), ZnBr/sup +/, ZnBr/sub 2/ (aq), ZnBr/sub 3//sup -/ and ZnBr/sub 4//sup 2 -/. By the use of peak heights or deconvolution/integration along with published Raman cross sections, the amount of each zinc species could be quantitatively determined. The addition of bromide ions to the zinc bromide solutions will shift the equilibrium toward higher bromide complexes. The added cations will influence the shifts. It has been noted that the conductivity of the electrolyte decreases when the quaternary ammonium ions are present compared to cations such as potassium or hydrogen. Significantly more free zinc is present in zinc bromide solutions with added KBr than with either MEMBr or HBr. Shifts are also noted with the other zinc ion containing species. It appears that the quaternary ammonium ions and possibly the pH could have a stabilizing effect on zinc bromide complex ion formation. 2 figs.

• Research Organization: Exxon Research and Engineering Co., Annandale, NJ (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5622754
• Report Number(s): SAND-85-7196C; CONF-851048-2; ON: DE85011820
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250903* -- Energy Storage-- Batteries-- Materials
Components
& Auxiliaries
ALKALI METAL COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
COMPLEXES
DATA
ELECTRIC BATTERIES
ELECTROCHEMICAL CELLS
ELECTROLYTES
ELECTROMAGNETIC RADIATION
EQUILIBRIUM
EXPERIMENTAL DATA
HALIDES
HALOGEN COMPOUNDS
HYDROBROMIC ACID
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
LASER RADIATION
LASER SPECTROSCOPY
NUMERICAL DATA
ORGANIC COMPOUNDS
POTASSIUM BROMIDES
POTASSIUM COMPOUNDS
QUATERNARY COMPOUNDS
RADIATIONS
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SPECTRA
SPECTROSCOPY
ZINC BROMIDES
ZINC COMPLEXES
ZINC COMPOUNDS
ZINC HALIDES