Manganese dioxide(MnO2),a commonly used cathode material for zinc-ion batteries(ZIBs),has attracted considerable attention owing to its abundant reserves in nature,safety,and high theoretical capacity.One of the key challenges in the preparation of high-performance zinc-ion batteries is the construction of a cathode with a stable microstructure.In this study,a flexible and conductive carbon cloth(CC)was chosen as the substrate onto which manganese dioxide(MnO2)was deposited through either reductive deposition or electrochemical deposition methods to form a carbon cloth@manganese dioxide(CC@MnO2)cathode.For the reductive deposition method,a precursor solution of KMnO4 and H2SO4 was used,and various concentrations were adopted to synthesize the CC@MnO2 cathode.The synthesized electrode is referred to as the CC@MnO2-reductive deposition cathode.Specifically,KMnO4 solutions with concentrations of 0.25,0.40,and 0.55 mol·L-1 were mixed with H2SO4 at concentrations of 0.20 mol·L-1 and 0.50 mol·L-1.For the electrochemical deposition method,MnO2 nanoparticles were decorated on CC using a three-electrode system under the potentiostatic mode at a potential of 1.1 V for 1500 s.A depositing electrolyte consisting of 0.1 mol·L-1 MnSO4+0.1 mol·L-1 Na2SO4 was used.The synthesized electrode is referred to as the CC@MnO2-electrochemical deposition cathode.The cathodes synthesized under different parameters were comparatively analyzed via scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and X-ray photoelectron microscopy to explore their morphology and microstructure.Furthermore,the prepared CC@MnO2 cathodes were assembled into button-type zinc-ion batteries,and their electrochemical properties,charging/discharging performance,and cycling stability were evaluated.The test results showed that the Zn//CC@MnO2 cells based on the reductive deposition method with a 0.40 mol·L-1 KMnO4+0.50 mol·L-1 H2SO4 mixed solution delivered optimal zinc storage performance(providing a discharge-specific capacity of up to 291 mA·h·g-1 at a current density of 0.1 A·g-1),energy density of 293.3 W·h·kg-1),and cycling stability with a capacity retention of 90.48％after 1000 cycles at a current density of 1 A g-1 and Coulomb efficiency of 99.87％.The superior electrochemical performance of the CC@MnO2-RD cathode compared with that of the CC@MnO2-ED cathode is attributable to the improved structural stability and uniformity of the former.In addition,a reversible two-step insertion storage mechanism involving H+and Zn2+in the CC@MnO2 cathode for ZIBs was verified through ex-situ X-ray diffraction and scanning electron microscopy measurements at different charging/discharging states.This paper highlights the optimized preparation process of CC@MnO2 electrodes based on the reductive deposition method,demonstrating advantages such as low cost and ease of fabrication.These findings can serve as a reference for developing high-performance zinc-ion batteries.
维普
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