Solar Energy Storage Using a Cu₂ O-TiO₂ Photocathode in a Lithium Battery

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Developing efficient energy storage solutions is crucial for integrating renewable energy sources.
• Photoelectrodes offer a pathway for direct solar energy conversion and storage.
• Existing technologies often face limitations in efficiency and integration.

Purpose of the Study:

• To propose and investigate a novel Cu₂O-TiO₂ photoelectrode for simultaneous solar energy harvesting and electrochemical energy storage.
• To demonstrate the feasibility of a photorechargeable lithium button cell utilizing this photoelectrode.
• To analyze the energy storage performance and efficiency of the developed device.

Main Methods:

• Fabrication of a p-type Cu₂O semiconductor layer integrated with a TiO₂ capacitive layer to form the photoelectrode.
• Assembly of the photoelectrode into an adapted lithium coin cell configuration.
• Characterization of the photoelectrode's performance under visible white light, including charge generation, lithiation/delithiation processes, and energy storage capacity.

Main Results:

• The Cu₂O-TiO₂ photoelectrode successfully harvested solar energy and stored electrochemical energy within a lithium coin cell.
• The photorechargeable cell demonstrated recharging capability with visible white light in approximately 9 hours under open circuit conditions.
• The device achieved an energy density of approximately 150 mAh g⁻¹ at a 0.1 C discharge current in the dark, with an overall efficiency of 0.29%.

Conclusions:

• The developed Cu₂O-TiO₂ photoelectrode presents a promising approach for integrated solar energy harvesting and electrochemical storage.
• This work advances the concept of photoelectrodes for monolithic rechargeable battery applications.
• The findings pave the way for next-generation energy storage devices with enhanced functionality.