The low cost, high theoretical specific capacity (617 mAh g-1) and environmentally benign nature of MnO2 makes it a very attractive material for a host of electrical energy storage applications such as aqueous based Zn/MnO2 batteries or non-aqueous Li/MnO2 batteries and even supercapacitors. Realizing higher energy and power densities in γ- MnO2 cathodes is of crucial interest for both primary as well as secondary battery applications. But achieving a long lasting high energy density rechargeable MnO2 battery suffers from many setbacks. Prime among these setbacks is the inability of γ- MnO2 polymorph to retain its structural integrity when cycled to deeper depths of discharge (DOD). The most widely used model for γ- MnO2 discharge consists of a solid state proton-electron intercalation process upto the 1st electron forming MnOOH and a dissolution-precipitation process during the 2nd electron discharge forming Mn(OH)2. In this paper, we investigate the cycle life degradation mechanism of the γ- MnO2 polymorph in alkaline environment in the 1st electron region of discharge. We conduct three-electrode experiments on 80 wt. % loading γ- MnO2 cathodes to determine the failure mechanism in various KOH concentrations and at various depths of discharge. At 50 % DOD of the 1st electron, we find a significant effect of KOH concentration with upto 70 % retention of discharge capacity over 100 charge-discharge cycles in 10 wt. % KOH compared to only 20 cycles in 37 wt. % KOH. At 40 % DOD of the 1st electron of MnO2, we observe an astounding 177 % improvement in cycle life in 10 wt. % KOH in comparison to poor recyclability observed in 37 % KOH. Post mortem X-ray diffraction analysis revealed the presence of birnessite, δ- MnO2, in the cathode with nanoflower, nanosheet and nanowire morphologies of birnessite observed in 37 wt. %, 25 wt. % and 10 wt. % KOH respectively. To probe into the failure mechanism we conducted four-electrode Pt- wire experiments to detect Mn (III) soluble species during discharge, in-situ. The experiments indicate significant influence of KOH concentration with Mn(III) dissolution, as determined by the presence of δ-MnO2 deposited on the Pt wire, being detected in 37 wt. % KOH at just ~34 % DOD during the 1st electron discharge. We propose, in this paper, that the capacity fade of γ- MnO2 at high DOD of 1st electron is critically related to the amount of birnessite, which is formed during the charging of Mn (III) ions. Since birnessite discharges at a much lower potential than cycled to in our experiments, its contribution to discharge capacity in the 1st electron region of γ- MnO2 is negligible and hence, builds up as an inactive phase, ultimately resulting in capacity fade. Figure 1