use of a selectively conducting anode component in solid polymer electrolyte fuel cells can reduce the degradation associated with repeated startup and shutdown , but unfortunately can also adversely affect a cell &# 39 ; s tolerance to voltage reversal . use of a carbon sublayer in such cells can improve the tolerance to voltage reversal , but can adversely affect cell performance . however , employing an appropriate selection of selectively conducting material and carbon sublayer , in which the carbon sublayer is in contact with the side of the anode opposite the solid polymer electrolyte , can provide for cells that exhibit acceptable behaviour in every regard . a suitable selectively conducting material comprises platinum deposited on tin oxide .