Solar Water Splitting Device Integrated Carbon-Based Electrodes and Carbon-Based Perovskite Solar Cells

Abstract

Producing hydrogen from integrated devices by solar-driven water splitting (SWS) is one of the most attractive methods for renewable energy conversion. However, their widespread use is hindered by their cost and poor performance. In this work, we developed an integrated device consisting of three series-connected carbon-based multi-porous-layered-electrode perovskite solar cells (MPLE-PSCs) 1-5 and carbon-based catalyst-decorated electrode couples (Figure 1a). Porous carbon electrodes with a graphite and carbon black mixture are used for the back contacts of solar cells, and pencil-lead graphite rods (PGRs) are used as electrocatalyst supports for water-splitting cells, which are much cheaper than existing materials. The performance of the PSC was compared between the 2 and 3-series, and the performance of the water-splitting cell with/without catalyst. In addition, each combination was compared.The solar to electricity efficiency (STE, same as power conversion efficiency: PCE) was 13.79% and 13.16% for the 2-series and 3-series, respectively. The electricity to hydrogen efficiency (ETH), calculated as V theoritical/V operating, 6 was 78.34% and 84.83%, for PGR and NiFe/PGR respectively. Furthermore, the matching factor (MF), calculated as (V operating × J operating)/(V max × J max), 6 for the <2-series PSCs>/<PGR> combination and the <3-series PSCs>/<NiFe/PGR> combination were 48.57% and 83.77%, respectively. Solar to hydrogen efficiency (STE), calculated as STE ×ETH × MF, improved from 5.25% to 9.35% for the optimized device (Figure 1b). These results show that low-cost and high-efficiency solar hydrogen can be produced by using Earth-abundant materials and by adjusting the maximum output of the device.(1) A. Mei, et al., Science 345, 295 (2014).(2) R. Tsuji, et al., Electrochemistry 88, 418 (2020).(3) R. Tsuji, et al., Photonics 7, 133 (2020).(4) D. Bogachuk, R. Tsuji, et al., Carbon 178, 10 (2021).(5) E. Kobayashi, R. Tsuji, et al., Cell Rep. Phys. Sci. 2, 100648 (2021).(6) Z. N. Zahran, et al., ACS Appl. Energy Mater. 5, 8241 (2022).Figure 1. Carbon-based solar water splitting. (a) Schematic diagram and (b) J-V curves of MPLE-PSCs and LSV curves of water electrolysis with PGR electrodes. Figure 1