Under the spotlight for their potential to reduce over-potential, photo-assisted Li–O 2 batteries still face a key challenge: the rapid recombination of photo-generated electron-hole pairs, which limits their efficiency. In this study, we address this limitation by designing a Li–O 2 battery that integrates both photo and magnetic field assistance, using an S-scheme MXene/In 2 S 3 /CoFe 2 O 4 heterojunction photocathode. This unique combination enhances visible light absorption and generates a strong built-in electric field, facilitating effective charge separation and boosting photocatalytic activity. During discharge, photo-generated electrons participate in the oxygen reduction reaction, while photo-induced holes contribute to the decomposition of discharge products during charging. Furthermore, the introduction of a magnetic field, confirmed through vibrating sample magnetometer, Mössbauer spectroscopy, X-ray absorption near edge structure, and cyclic voltammetry analyses, enhances electron-hole separation via Lorentz forces and spin–orbit coupling, accelerating the formation and decomposition of Li 2 O 2 . With this synergistic approach, the battery achieves a high specific capacity of 26,500 mAh g −1 , ultra-low oxygen reduction/evolution reaction over-potentials of 0.08 V/0.17 V, and a long cycle life of 2000 cycles with energy efficiency of 98.11 %. This work demonstrates the promising potential of combining photo and magnetic field effects to improve the electrochemical performance of Li–O 2 batteries, opening new avenues for high-performance energy storage systems.
Kang Hu,Tingsong Hu,Tengyu Yao,Xueliang Cui,Qiuju Li,Laifa Shen
Li–CO2 batteries are considered promising energy storage systems for implementation in space applications. However, unsatisfactory overpotentials and poor cycling stability caused by the sluggish reaction kinetics of CO2 reduction and evolution have greatly limited the practical application of Li–CO2 batteries. Herein, we introduce a redox mediator LiI to stabilize the Bi5O7I photocathode by the successive separation of electrons and holes to accelerate the sluggish kinetics. Under illumination, LiI allows photogenerated holes to preferentially react with I– in the solid–liquid interface, thereby inhibiting the release of I– from Bi5O7I and effectively improving the lifespan of the photocathode. Thus, a high discharging platform of 3.05 V and an ultralow charging platform of 3.09 V are achieved to exhibit an energy efficiency of 98.8%. Moreover, a significantly enhanced reversibility is attained, attributed to the decomposition of Li2CO3, which further extends the cycle life to 250 h. This double-phase catalytic strategy demonstrates effectiveness in the development of high-performance Li–CO2 batteries and other energy storage devices.
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