Photo-Rechargeable Energy Storage Systems

Photo-rechargeable energy storage systems integrate light-harvesting and electrochemical storage within a single device architecture, enabling direct conversion of solar radiation into chemical energy without intermediary wiring or external solar modules. At their core, these systems rely on photoactive electrodes—commonly photocathodes or photoanodes—that absorb photons to generate charge carriers, which then drive redox reactions in battery or capacitor components. Architectures range from dye-sensitised hybrid electrodes to perovskite-integrated cells and carbon-based bifunctional materials, each aiming to balance energy density, conversion efficiency and cycle life. Such devices hold promise for decentralised power supply in off-grid sensors, portable electronics and electric vehicles, while mitigating inefficiencies associated with separate photovoltaic and storage units. Key challenges include optimising interfacial charge separation, managing thermal versus optical contributions during illumination, standardising performance metrics and engineering durable materials that combine high specific energy with rapid photocharge kinetics.

Research from Nature Portfolio

One report describes a monolithic device combining a perovskite solar module and an aqueous zinc battery in a shared electrode assembly. The sandwich-joint structure unites light conversion and energy storage, delivering a specific power of over 50 kW kg^–1 and a specific energy approaching 370 Wh kg^–1, with photocharge efficiencies near 6% and stable performance over hundreds of cycles. Another study demonstrated that illuminating a LiMn₂O₄ cathode during charging can halve the charge time. Light induces a microsecond-scale charge-separated state, enhancing metal-centre oxidation and expediting lithium extraction without compromising capacity. Earlier foundational work combined dye-sensitised electrodes with LiFePO₄ nanoparticles to achieve direct light-driven delithiation, leveraging hole injection to oxidise the cathode and using the resultant electrons for solid-electrolyte-interface formation at the anode. This hybrid photo-battery concept established key design principles for coupling photochemistry with intercalation dynamics.

Photo-Rechargeable Energy Storage Systems publication trend

The graph below shows the total number of articles in photo-rechargeable energy storage systems across all publications each year (not limited to Nature Index journals).

Technical terms

Photocharging: Direct replenishment of stored chemical energy in a device by photon absorption, without external electrical input.

Photocathode: An electrode that absorbs light to generate electrons or holes, initiating redox reactions for energy storage.

Photoconversion efficiency: Ratio of chemical energy stored to incident photon energy under specified illumination.

Delithiation: Removal of lithium ions from an electrode material during charging, often driven here by photo-induced hole injection.

Heterojunction: Interface between two semiconductor materials that facilitates charge-separation and transport via energy-band alignment.

References

1. Coupling aqueous zinc batteries and perovskite solar cells for simultaneous energy harvest, conversion and storage. Nature Communications (2022).
2. Photo-accelerated fast charging of lithium-ion batteries. Nature Communications (2019).
3. Light-assisted delithiation of lithium iron phosphate nanocrystals towards photo-rechargeable lithium ion batteries. Nature Communications (2017).
4. Integrated Solar Batteries: Design and Device Concepts. ACS Energy Letters (2023).
5. An integrated solar battery based on a charge storing 2D carbon nitride. Energy & Environmental Science (2023).