Rechargeable neutral aqueous zinc−air batteries (ZABs) are a promising type of energy storage device with longer operating life and less corrosiveness compared with conventional alkaline ZABs. However, the neutral ZABs normally possess poor oxygen evolution reactions (OERs) and oxygen reduction reactions performance, resulting in a large charge–discharge voltage gap and low round-trip efficiency. Herein, we demonstrate a sunlight-assisted strategy for achieving an ultralow voltage gap of 0.05 V in neutral ZABs by using the FeOOH-decorated BiVO₄ (Fe-BiVO₄) as an oxygen catalyst. Under sunlight, the electrons move from the valence band (VB) of Fe-BiVO₄ to the conduction band producing holes in VB to promote the OER process and hence reduce the overpotential. Meanwhile, the photopotential generated by the Fe-BiVO₄ compensates a part of the charging potential of neutral ZABs. Accordingly, the energy loss of the battery could be compensated via solar energy, leading to a record-low gap of 0.05 V between the charge and discharge voltage with a high round-trip efficiency of 94%. This work offers a simple but efficient pathway for solar-energy utilization in storage devices, further guiding the design of high energy efficiency of neutral aqueous ZABs.

中文翻译：

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阳光响应型中性水性锌空气电池的超低充放电电压间隙为 0.05 V

可充电中性水性锌空气电池（ZAB）是一种很有前途的储能装置，与传统的碱性 ZAB 相比，它具有更长的使用寿命和更低的腐蚀性。然而，中性ZAB通常具有较差的析氧反应（OER）和氧还原反应性能，导致充放电电压差距较大和往返效率较低。在此，我们展示了一种阳光辅助策略，通过使用 FeOOH 修饰的 BiVO ₄ (Fe-BiVO ₄ ) 作为氧催化剂，在中性 ZAB 中实现 0.05 V 的超低电压间隙。在阳光下，电子从Fe-BiVO ₄的价带(VB)移动到导带，在VB中产生空穴，促进OER过程，从而降低过电势。同时，Fe-BiVO ₄产生的光势补偿了中性ZABs的部分充电势。因此，电池的能量损失可以通过太阳能进行补偿，从而使充放电电压之间的差距达到创纪录的0.05 V，并且往返效率高达94%。这项工作为存储装置中的太阳能利用提供了一种简单而有效的途径，进一步指导了中性水ZAB的高能效设计。