Li-O_(2)batteries are regarded as one of the most promising next-generation battery systems due to their high theoretical energy density,finding effective cathode catalysts with fine-tuned structure is a key way to im...Li-O_(2)batteries are regarded as one of the most promising next-generation battery systems due to their high theoretical energy density,finding effective cathode catalysts with fine-tuned structure is a key way to improve the performance.Herein,based on the structure of cubic zeolitic imidazolate framework-67(ZIF-67),a series of hollow catalysts were synthesized by different chemical etching treatments.Firstly,from the perspective of metal,nickel nitrate is used for etching,hollow Ni ZIF is obtained through Kirkendall effect.Secondly,hollow TA-ZIF is obtained by adding tannic acid to replace the methylimidazole ligand.Hollow structures have larger surface areas,materials can expose more active sites,which can lead to better performance of Li-O_(2)batteries.On this basis,having more oxygen vacancies can also improve the battery performance.At the same time,further loading noble metal ruthenium on the synthesized cobalt-based catalyst can effectively reduce the overpotential of Li-O_(2)battery and improve the battery performance.For TA-ZIF with more stable hollow structure and more oxygen vacancies,the cycle performance reaches 330 cycles after loading Ru.Compared with the 64 cycles of solid Co_(3)O_(4),it has a great improvement.展开更多
基金the National Natural Science Foundation of China(Nos.21606021 and 21771024).
文摘Li-O_(2)batteries are regarded as one of the most promising next-generation battery systems due to their high theoretical energy density,finding effective cathode catalysts with fine-tuned structure is a key way to improve the performance.Herein,based on the structure of cubic zeolitic imidazolate framework-67(ZIF-67),a series of hollow catalysts were synthesized by different chemical etching treatments.Firstly,from the perspective of metal,nickel nitrate is used for etching,hollow Ni ZIF is obtained through Kirkendall effect.Secondly,hollow TA-ZIF is obtained by adding tannic acid to replace the methylimidazole ligand.Hollow structures have larger surface areas,materials can expose more active sites,which can lead to better performance of Li-O_(2)batteries.On this basis,having more oxygen vacancies can also improve the battery performance.At the same time,further loading noble metal ruthenium on the synthesized cobalt-based catalyst can effectively reduce the overpotential of Li-O_(2)battery and improve the battery performance.For TA-ZIF with more stable hollow structure and more oxygen vacancies,the cycle performance reaches 330 cycles after loading Ru.Compared with the 64 cycles of solid Co_(3)O_(4),it has a great improvement.
