Although metal oxide compounds are considered as desirable anode materials for potassium-ion batteries(PIBs)due to their high theoretical capacity,the large volume variation remains a key issue in realizing metal oxid...Although metal oxide compounds are considered as desirable anode materials for potassium-ion batteries(PIBs)due to their high theoretical capacity,the large volume variation remains a key issue in realizing metal oxide anodes with long cycle life and excellent rate property.In this study,polypyrroleencapsulated Sb_(2)WO_(6)(denoted Sb_(2)WO_(6)@PPy)microflowers are synthesized by a one-step hydrothermal method followed by in-situ polymerization and coating by pyrrole.Leveraging the nanosheet-stacked Sb_(2)WO_(6)microflower structure,the improved electronic conductivity,and the architectural protection offered by the PPy coating,Sb_(2)WO_(6)@PPy exhibits boosted potassium storage properties,thereby demonstrating an outstanding rate property of 110.3 m A h g^(-1)at 5 A g^(-1)and delivering a long-period cycling stability with a reversible capacity of 197.2 m A h g^(-1)after 500 cycles at 1 A g^(-1).In addition,the conversion and alloying processes of Sb_(2)WO_(6)@PPy in PIBs with the generation of intermediates,K_(2)WO_(4)and K_(3)Sb,is determined by X-ray photoelectron spectroscopy,transmission electron microscopy,and exsitu X-ray diffraction during potassiation/depotassiation.Density functional theory calculations demonstrate that the robust coupling between PPy and Sb_(2)WO_(6)endues it with a much stronger total density of states and a built-in electric field,thereby increasing the electronic conductivity,and thus effectively reduces the K^(+)diffusion barrier.展开更多
基金supported by the National Natural Science Foundation of China(22075147 and 22179063)。
文摘Although metal oxide compounds are considered as desirable anode materials for potassium-ion batteries(PIBs)due to their high theoretical capacity,the large volume variation remains a key issue in realizing metal oxide anodes with long cycle life and excellent rate property.In this study,polypyrroleencapsulated Sb_(2)WO_(6)(denoted Sb_(2)WO_(6)@PPy)microflowers are synthesized by a one-step hydrothermal method followed by in-situ polymerization and coating by pyrrole.Leveraging the nanosheet-stacked Sb_(2)WO_(6)microflower structure,the improved electronic conductivity,and the architectural protection offered by the PPy coating,Sb_(2)WO_(6)@PPy exhibits boosted potassium storage properties,thereby demonstrating an outstanding rate property of 110.3 m A h g^(-1)at 5 A g^(-1)and delivering a long-period cycling stability with a reversible capacity of 197.2 m A h g^(-1)after 500 cycles at 1 A g^(-1).In addition,the conversion and alloying processes of Sb_(2)WO_(6)@PPy in PIBs with the generation of intermediates,K_(2)WO_(4)and K_(3)Sb,is determined by X-ray photoelectron spectroscopy,transmission electron microscopy,and exsitu X-ray diffraction during potassiation/depotassiation.Density functional theory calculations demonstrate that the robust coupling between PPy and Sb_(2)WO_(6)endues it with a much stronger total density of states and a built-in electric field,thereby increasing the electronic conductivity,and thus effectively reduces the K^(+)diffusion barrier.
