Monolithic integration of aluminum-graphite batteries with silicon solar cells for direct energy conversion and storage

Silicon solar cells are a key technology for converting sunlight into electricity. However, their intermittent power output requires integration with suitable energy storage systems. Conventional photovoltaic-battery systems typically rely on external wiring, charge controllers, and power conversion components, which increase system complexity and introduce additional energy losses. Here, an aluminum-graphite battery was directly integrated with silicon solar cells to demonstrate direct photo-charging without intermediate power conversion electronics. Direct integration of the battery with the solar cell eliminates losses associated with external converters and wiring, resulting in a simpler and potentially more efficient system. When the aluminum-graphite battery was integrated with silicon solar cells connected in series, a charging potential of 2.4 V was generated under a solar irradiance of 1000 W/m 2 and the battery delivered a specific discharge capacity of 112 mAh/g after 30 min of light exposure and at a specific discharge current of 25 mA/g, similar to its galvanostatic charge-discharge behavior. These results demonstrate the feasibility of directly photo-charging an aluminum-graphite battery with silicon solar cells.