Inserting a photoelectrode into the cathode side of the Li–O₂ battery has been considered as one of the effective ways to improve the reaction kinetics of Li₂O₂ and reduce the discharge/charge overpotential. Thus, the development of compatible bifunctional photoelectrode is of great significance for the realization of a solar-assisted Li–O₂ battery. Herein, hexagonal-phase borophene nanosheets (HPBNs) were prepared by I₂ oxidizing layered MgB₂ in a mixture of CH₃CN and HCl and followed by ultrasonic exfoliation. Based on the I₂ oxidizing and chelating action along with precise thermodynamic regulation, 94% Mg²⁺ ions were maximally extracted from MgB₂ for achieving hexagonal-phase borophene with typical parallel planes of (104) and (208). The obtained HPBNs were assigned to direct band gap semiconductor with a band gap of 2.61 eV enabling massive visible light absorption and displayed applicable potentials for Li₂O₂/O₂ redox. The assembled photoassisted Li–O₂ battery exhibited a high round-efficiency of 98% and a long cycle and superior rate performance at 1 mA cm^–2. It is of particular concern that the HPBNs-based Li–O₂ battery be enabled to operate under outdoor solar along with a comparable performance of photoassisted Li–O₂ battery under Xe lamp. This work could provide promising insight for accelerating applications of bifunctional photoelectrodes in solar-assisted Li–O₂ batteries.

中文翻译：

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能够驱动高性能太阳能辅助 Li-O2 电池的六方相硼烯纳米片双功能光电电极


将光电极插入 Li-O₂ 电池的阴极侧被认为是改善 Li₂O₂ 反应动力学和减少放电/充电过电位的有效方法之一。因此，开发兼容的双功能光电极对于实现太阳能辅助 Li-O₂ 电池具有重要意义。在此，通过 I₂ 氧化层状 MgB₂ 在 CH₃CN 和 HCl 的混合物中制备六方相硼烯纳米片 （HPBN），然后进行超声剥离。基于 I₂ 氧化和螯合作用以及精确的热力学调节，从 MgB₂ 中最大限度地提取了 94% 的 Mg²⁺ 离子，以获得具有 （104） 和 （208） 典型平行平面的六方相硼吩。获得的 HPBN 被分配到带隙为 2.61 eV 的直接带隙半导体上，能够实现大规模可见光吸收，并显示出对 Li₂O₂/O₂ 氧化还原的适用电位。组装的光辅助_{Li-O 2} 电池在 1 mA cm^–2 时表现出 98% 的高圆周效率和长周期和卓越的倍率性能。特别令人担忧的是，基于 HPBNs 的 Li-O₂ 电池能够在户外太阳能下运行，并且在 Xe 灯下具有与光辅助_{Li-O 2} 电池相当的性能。这项工作可以为加速双功能光电极在太阳能辅助_{Li-O 2} 电池中的应用提供有前途的见解。