Saving electric energy by integrating a photoelectrode into a Li-ion battery

We here report a novel photoassisted chargeable Li-ion battery (LIB) consisting of a LiFePO4 cathode, a lithium anode and a TiO2 photo-electrode coupled with an iodide (I-) ion redox shuttle for saving electric energy. Due to the contribution of the photovoltage, the photocharging voltage of the LiFePO4 cathode is reduced to 2.78 V, which is lower than the discharge voltage of 3.41 V, resulting in similar to 20% electric energy saving. This new conceptual design will provide a possible route for direct conversion and storage of solar energy in LIBs.