The historically poor electrochemical rechargeability of Zn in alkaline electrolyte has hindered the commercial viability of Ni-Zn batteries, a system otherwise of interest because of high specific energy (up to 140 Wh kg(-1)). We have redesigned the Zn anode as a three-dimensional (3D), monolithic porous architecture (" sponge") that exhibits unprecedented Zn specific capacity and dendrite-free cycling. Maintaining the integrity of the 3D Zn sponge architecture throughout charge-discharge is required to ultimately achieve technologically relevant performance in terms of cycle life and capacity. En route to this goal, we systematically evaluated a series of electrolyte and electrode additives used in conjunction with our Zn sponge anode in order to down-select formulations that minimize electrode shape change with cycling in prototype Ni-3D Zn cells. The classes of additives chosen for this study include those that either inhibit ZnO passivation during discharge (Type I: LiOH, K2SiO3) or promote it (Type II/III: KF, K2CO3, ZnO, Ca(OH)(2)), as well as combinations thereof. We find that the second class of additives effectively retains the cycled Zn sponge in its pre-cycled condition. (C) 2015 The Electrochemical Society. All rights reserved.