Figure also shows the fade rate for the case when 0-85% SOC restriction and the regeneration are both integrated into the cell cycling. The measured fade rate in 1.0 M OH -is around 0.05%/day (18.3%/year) but it decreases to 0.02%/day (7.3%/year) in 1.5 M OH -. Nonetheless, the fade rate remains unchanged when OH -concentration is further increased to 2.0 M. Therefore, there is no benefit to the fade rate by increasing the OH -concentration beyond 1.5 M when both SOC restriction and regeneration are implemented. This observation is related to a lower recovery efficiency. As shown in Figure , the recovery efficiency decreases to 74% in 2.0 M OH -. Although the lowest fade rate is obtained in 2M OH - under both 100% cycling and 0-85% cycling conditions, the fade rate in the presence of the regeneration is not lowered because the recovery efficiency is the lowest in 2.0 M OH -.