Structure and electrochemical properties of hierarchically porous carbon nanomaterials derived from hybrid ZIF-8/ZIF-67 bi-MOF coated cyclomatrix poly(organophosphazene) nanospheres. (27th February 2020)

• Record Type: Journal Article
• Authors: Zhou, Yutao; Wemyss, Alan M.; Brown, Oliver B.; Huang, Qianye; Wan, Chaoying
• Is Part Of: New journal of chemistry. Volume 44:Number 11(2020)
• Page Start: 4353
• Page End: 4362
• Publication Date: 2020-02-27
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d0nj00040j
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Hierarchically porous carbon nanostructures with intrinsically doped heteroatoms and metal elements are attractive for electrochemical energy storage applications. Abstract : Hybrid bi-ZIF nanocrystals consisting of ZIF-8/ZIF-67 were synthesised in the presence of cyclomatrix poly(organophosphazene) (POP) nanospheres and formed POP/bi-ZIF core@shell nanospheres. POP/bi-ZIF showed excellent thermal stability up to 478 °C, with well-preserved core@shell structures during carbonization at 850 °C. The resultant core@shell carbon nanospheres exhibited hierarchically mesoporous structures. The porous carbon core was derived from the carbonised covalent inorganic–organic polyphosphazene framework, containing in situ doped heteroatoms such as N, P, S and O; the shell structure was derived from bi-ZIF containing up to 40% Zn and Co elements. The bi-ZIF derived carbon shell showed a BET surface area of 1347.76 m 2 g −1 and a Langmuir surface area of 1882.71 m 2 g −1, and the total BET surface area of the core@shell structure reached 1025.00 m 2 g −1 . When applied as an anode material in lithium ion batteries, the core@shell carbon structure exhibited a charge capacity of 595 mA h g −1 with a discharge capacity of 546 mA h g −1 and maintained a reversible charge/discharge capacity of 400 mA h g −1 after 140 cycles, which is higher than the theoretical capacity of a graphite anode. A good cycling stability with 83% capacity retention in the C-rate tests was achieved. This work provides a facile and scalable method to produce mesoporous carbon nanostructures with in situ doped metal elements and heteroatoms, which benefits the high rate electrochemical properties of lithium ion batteries.