Modes of photoelectrochemical storage

Conversion of a regenerative PEC to a PECS can incorporate several increasingly sophisticated solar energy conversion and storage configurations, which we shall discuss in this section. 

Schematic diagram of two-electrode storage cells with (a) an insoluble redox storage 

SPE = semiconductor photoelectrode, CE = counter electrode. At the electrode I electrolyte interface, redox couples A and B are either in solution (I Redox ), or confined to the counter electrode ( RedoxoE-CE) or the semiconductor photoelectrode (SPE-RedoxspE I )  

As Manassen et al. (1981) pointed out, the configurations represented in Fig. 10.5 have another disadvantage, namely the disparity between the small surface area desired to minimise the dark current in the storage electrode or half-cell, since this opposes and reduces the photocurrent, and the large surface area necessary to minimise storage polarisation losses and maximise storage capacity. 

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