近日，2022级研究生李媛在SCI二区期刊Journal of Energy Storage (IF=8.9) 发表具有可控空腔的蛋黄壳结构ZnO@N-掺杂碳作为锂离子电池负极“Yolk-shell structured ZnO@N-doped carbon with controllable cavity as anode of lithium ion battery”。

原文链接：https://doi.org/10.1016/j.est.2024.115143

Abstract

Yolk-shell structured ZnO@N-doped carbon with controllable cavity as anode materials of lithium ion batteries (LIBs) is attracting extensively interest because it can effectively alleviate the damage caused by the huge volume expansion of ZnO. Here, covalent organic frameworks (COFs)-derived N-doped porous carbon (NC)-coated ZnO nanocomposites with controllable yolk-shell (YS) structure (YS-ZnO@NC) was synthesized by a self-template method. The strategy firstly prepared covalent organic polymers (COPs) coated ZnO nanocomposites with core-shell (CS) structure (CS-ZnO-60@COPs). Then YS-ZnO@COFs were obtained by immersing CS-ZnO- 60@COPs in acetic acid. Acetic acid was used not only as catalyst to transform COPs into COFs but also as etching agent to etch ZnO. In the transform process from COPs into COFs, a small internal cavity was formed and the internal cavity was further enlarged by etching ZnO, which can effectively control the size of internal cavity and ZnO by adjusting amount of acetic acid. Finally, the YS-ZnO@NC was formed by high-temperature calcination of YS-ZnO@COFs. The COFs-derived well-ordered carbon networks provide a large number of evenly distributed well-ordered pores which are conducive to Li⁺ storage. Thanks to the unique yolk-shell structure and the well-ordered carbon network, the YS-ZnO@NC-23 has excellent Li-storage capacity. At 0.2 A g^-1, YSZnO@NC-23 as anode materials of LIBs has a high initial discharge specific capacity of 1772.3 mAh g^-1. After 500 cycles, it was still maintained at 1267.5 mAh g^-1. This strategy based on self-template method provides a new choice for the preparation of high performance LIBs anode nanocomposites.

Scheme 1. Schematic illustration for synthetic process of CS-ZnO@NC and YS-ZnO@NC.