The influence of water concentration on the electrochemical behavior of Al
anodes in Al/active-non-aqueous electrolytes is investigated. Normally pass
ive, Al exhibits facile electrochemical oxidation in both AlCl3/gamma-butyr
olactone (AlCl3/BLA) and (C2H5)(4)NCl acetonitrile (TEAC/ACN) electrolytes.
However, in these two electrolytes, the influence of water on Al oxidation
shows opposite effects. Incremental increase from 0 to 1.5 M H2O (0 to 3%
water by volume) hinders Al oxidation in 1 M AlCl3/BLA, increasing polariza
tion loss from 100 to 400 mV cm(2) mA(-1). Yet in 0.3 M TEAC/ACN, Al is pas
sive in the absence of water, exhibiting currents only in the mu A cm(-2) d
omain, equivalent to oxidative polarization losses of over 1000 mV cm(2) mA
(-1). This polarization loss is alleviated by water addition, and decreases
from 20 to 7 mV cm(2) mA(-1) as water is increased from 0.3 to 1.5 M. FT-I
R spectroscopy, linear voltammetry, galvanostatic reduction, surface micros
copy and electrolytic conductivity measurements were conducted to probe com
peting water activation or water passivation effects on organic-phase Al el
ectrochemistry. (C) 2000 Elsevier Science S.A. All rights reserved.