Bipolar fluorinated covalent triazine framework cathode with high lithium storage and long cycling capability.
Xiudong ChenHang ZhangPing YanBo LiuXiaohua CaoChangchao ZhanYawei WangJin-Hang LiuPublished in: RSC advances (2022)
Organic materials with adjustable structures and wide sources are expected to become potential candidates for commercial cathodes of lithium-ion batteries (LIBs). However, most organic materials have unstable structures, poor conductivity, and are easily soluble in electrolytes, resulting in unsatisfactory lithium storage performance. Covalent-organic frameworks have attracted extensive attention due to their stable frame structures, adjustable pore structures and functionalized official groups. Herein, a fluorinated covalent triazine framework (FCTF) is synthesized by a simple ion-thermal method. Compared with the fluorine-free covalent triazine frameworks (CTFs), the introduction of fluorine improves the lithium storage performance of CTF. When used as a cathode for lithium ion batteries, FCTF can retain a reversible capacity of 125.6 mA h g -1 after 200 cycles at a current density of 100 mA g -1 . Besides, it also delivers 106.3 mA h g -1 after 400 cycles at a current density of 200 mA g -1 with 0.03% decrease per cycle (from 40 to 400 cycles).