Chen Pengyu, Liu Wei, Wang Hao, Jiang Yao, Niu Xiaobin, Wang Liping
School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, China.
21C Innovation Laboratory, Contemporary Amperex Technology Ltd. (21C LAB), Ningde 352100, Fujian, China.
J Colloid Interface Sci. 2023 Nov;649:255-263. doi: 10.1016/j.jcis.2023.06.108. Epub 2023 Jun 19.
Fluorinated carbon (CF) cathodes possess the highest theoretical energy density among lithium primary batteries. However, achieving reversibility in CF remains a significant challenge. This work employs a high-voltage sulfolane electrolyte and achieves a highly reversible CF cathodes in lithium-ion batteries (LIBs) via fine modification of the C-F bond character. The improved reversibility of CF originates from the semi-ionic CF phase, with a superior bond length and weaker bond energy than a covalent bond. This characteristic significantly mitigates the challenges encountered during the charging process. We screen and identify the fluorinated graphene CF as a suitable cathode, providing an appropriate fluorine content and sufficient semi-ionic C-F bonds for rechargeable LIBs. This fluorinated graphene CF exhibits an initial discharge specific capacity of 814 mAh g and a reversible discharge specific capacity of 350 mAh g. This work provides a new clue for chemical bond regulation studies and provides insights into stimulating reversibility of primary-cell cathodes.
氟化碳（CF）阴极在锂原电池中具有最高的理论能量密度。然而，实现CF的可逆性仍然是一项重大挑战。这项工作采用了一种高压环丁砜电解质，并通过对C-F键特性的精细修饰，在锂离子电池（LIBs）中实现了高度可逆的CF阴极。CF可逆性的提高源于半离子CF相，其键长优于共价键，键能比共价键弱。这一特性显著减轻了充电过程中遇到的挑战。我们筛选并确定氟化石墨烯CF为合适的阴极，为可充电LIBs提供了合适的氟含量和足够的半离子C-F键。这种氟化石墨烯CF的初始放电比容量为814 mAh g，可逆放电比容量为350 mAh g。这项工作为化学键调控研究提供了新线索，并为激发原电池阴极的可逆性提供了见解。
