Figure 6. Cycling performance of the proposed SRFC.

(a) Photocharge curves of the SRFC in a 0.2 M HBr+0.005 M Br₂+1.0 M H₂SO₄ solution on the positive side and a 0.05 M AQDS+1.0 M H₂SO₄ solution on the negative side without the external bias under visible light illumination (100 mW cm⁻²). The surface area of C/TiO₂/Ti/n⁺p-Si is 0.232 cm² and that of Pt/p⁺n-Si is 0.230 cm². The photocurrent density is calculated based on the total illumination areas of photoanode and photocathode. The flow rates of the electrolytes are kept at 100 ml min⁻¹. (b) Galvanostatic discharge curves of the SRFC at constant current 2.0 mA cm⁻² under dark. (c) Discharge capacity and (d) overall photon–chemical–electricity energy conversion efficiency of the SRFC as a function of the cycle number.