Rubbish. That might be true of the SCiBs offered in JDM, but certainly not the GS Yuasa batteries that are our only choice in the U.S. "significant toll" is one hell of a wiggle word, and not one that should provide any reassurance whatever. You aren't going to be able to quote that for any benefit when you get to "hey, my battery capacity's down 25%" time, believe me. And I'd note that quote's back from 2011, when Mitsubishi was spinning many a tallish tale about many aspects of the i-MiEV - later comments have been considerably more subdued, especially in the wake of Nissan's Phoenix Fiasco.