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Manganese monoxide (MnO) currently has attracted increasing attention in aqueous zinc metal batteries (AZMBs) due to the high theoretical capacity, satisfactory output voltage, and low price. However, the development of a MnO cathode is still plagued by the low specific capacity arising from the sluggish reaction kinetics and rapid capacity decay induced by structural collapse. Herein, the oxygen-defect-rich MnO1–x integrated with a carbon nanofiber (MnO1–x @CNF) membrane is designed based on a facile electrospinning technique. In situ X-ray diffraction and ex situ X-ray photoelectronic spectroscopy results confirm the proton-dominated insertion electrochemistry during cycling. The theoretical calculation results revealed that the introduction of oxygen vacancies could effectively decrease the H+ diffusion energy barrier and thus promote H+ diffusion. In addition, CNFs could provide flexible and lightweight electron transport networks to ensure rapid electrode reaction kinetics. Consequently, the as-prepared MnO1–x @CNF cathode delivers a high specific capacity of 264 mAh g–1 at 0.1 A g–1 and an outstanding capacity retention after 2500 cycles at 2 A g–1. The high flexibility and light weight of the MnO1–x @CNF membrane may aid in future high-performance cathodes for wearable AZMBs.

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In this paper, a new copper complex of Cu(dapymt)·4H2O (CuDpy) with strong and stable orange fluorescence was synthesized by using 4,6-diamino-2-mercaptopyrimidine (dapymt) as the ligand. Based on the excellent luminescent property of CuDpy, a bifunctional ratiometric fluorescent probe of CuDpy-CDs was constructed adopting CuDpy as the response fluorescent signal and blue-emitting carbon quantum dots (CDs) as the reference fluorescent signal. In the selective identification of anion and cation, CuDpy-CDs probe can specifically identify Ag+ and S2-. The detection limits for Ag+ and S2- were 1.88 μM and 0.16 μM, respectively, while the detection linear range of CuDpy-CDs for ions were 0-400 μM and 0-35 μM, respectively. In addition, a CuDpy-CDs portable sensing gel was fabricated which can monitor the approximate concentration of Ag+ and S2- in wastewater by the color change of fluorescence.