Smart Solar–Metal–Air Batteries Based on BiOCl Photocorrosion for Monolithic Solar Energy Conversion and Storage

Abstract

Solar energy generation and storage are two distinct processes and integrating them in a single device is of great challenge. Herein, BiOCl hydrogel film electrode featuring excellent photocorrosion and regeneration properties acts as the anode to construct a novel type of smart Solar-Metal-Air Batteries (SMABs), which combine the characteristics of solar cell (direct photovoltaic conversion) and metal-air battery (electric energy storage and release interacting with atmosphere). The cyclic photocorrosion processes between BiOCl (Bi 3+ ) and Bi can simply be achieved by solar light illuminating and standing in dark, corresponding to the charging and discharging processes of the battery, respectively. Upon illumination, the device takes open-circuit configuration to charge itself from the sunlight. Photogenerated electrons in the conduction band of BiOCl reduce Bi 3+ to Bi 0 following the photocorrosion process of BiOCl; and in the meantime, photogenerated positive charges (holes) initiate the oxygen evolution reaction to produce O2. Notably, in this system, the converted solar energy can be stored in the SMABs without the need of external batteries to store the electricity like those for the traditional solar cells. In the discharging process in the dark, Bi 0 spontaneously turns back to Bi 3+ producing electrons to induce oxygen reduction reaction occurring at the counter electrode (Pt/C) like metal-air battery. With an illumination of 15 min, the battery with an electrode area of 1 cm 2 can be continuously discharged for approximately 3,000 s, demonstrating a theoretical capacity of 384.75 mAh•g -1 , which is higher than the theoretical capacity of lithium-ion batteries (LiCoO2, 274 mAh•g -1 ). This novel type of SMABs is developed for the first time based on the unique photocorrosive and self-oxidation reaction of BiOCl to achieve photochemical energy generation and storage. The revealed fundamental mechanism and proposed device design create new solutions to the renewable energy harvesting and storage field. This class of solar light direct-charging battery is an effective step to fulfill the need for green and sustainable energy developments and exhibits great promise for the commercial market.

Photocorrosion-Based BiOCl Photothermal Materials for Synergistic Solar-Driven Desalination and Photoelectrochemistry Energy Storage and Release

“…In our previous research, we have derived the photocorrosion mechanism of BiOCl, which is the process of self-redox of semiconductor photogenerated charges, as shown in Figure f, based on the redox potential of the photogenerated charges, the photogenerated electrons from the conduction band can reduce Bi 3+ to Bi 0 , and the photogenerated holes of the valence band can oxidize the adsorbed water molecules on the surface to generate oxygen. The photoetching process of BiOCl can be expressed by the following formula 4 normalB normali normalO normalC normall + 2 normalH 2 normalO + 12 normalh normalv → 4 normalB normali + 3 normalO 2 + 4 normalH + + 4 normalC normall − In reaction 1, a total of 12 electrons are transferred, and the electrons are generated by the excitation of photons, so the number of photons participating in the reaction is the same as the number of transferred electrons.…”

“…Bismuth oxychloride (BiOCl) is a common photocatalytic material with low cost and simple preparation process. In our previous work, the photocorrosion process of BiOCl was used as an energy storage medium for photoelectrochemical conversion of solar energy . Bi nanoparticles are generated during the photo-storage process.…”

Ionic liquid gel microspheres as an emerging platform for constructing liquid compartment microreactors

“…The slight decrease of the degradation rate may be attributed to the photocorrosion of BiOBr after long-term illumination. 72…”

“…The slight decrease of the degradation rate may be attributed to the photocorrosion of BiOBr after long-term illumination. 72 3.6 The reaction mechanism of the photocatalytic procedure in the BiOBr@ILG-microspheres…”

Next-generation applications for integrated perovskite solar cells

“…PV-integrated energy storage systems Solar energy will continue to be a leading source of renewable energy. However, conventional solar cells are instantaneous photoelectric conversion devices and the electrical output has to be consumed immediately or stored 139 . To address the need of uninterrupted energy availability it is therefore important to develop integrated energy conversion-storage systems.…”