摘要
氟化碳(CF_(x))作为锂一次电池正极材料,相比传统可逆正极具有显著的理论能量密度优势。因此,探索锂/氟化碳(Li/CF_(x))电池的二次化应用可能性对于发展高能量密度储能体系具有战略意义,而相关机理与策略研究目前仍较缺乏。本研究工作系统揭示了CF_(x)转化反应过程的氟化锂(LiF)沉积行为,发现循环早期纳米晶态LiF可进行一定程度的分解从而贡献可逆容量,而随着循环进行,其尺寸逐步生长导致分解动力学受限并引发可逆容量衰减。在此基础上,提出引入苄胺三氟化硼络合物作为电解液添加剂进行转化过程调控,以实现Li/CF_(x)电池二次化的初步应用。电镜、光谱及能谱等表征手段证实了该络合物抑制LiF颗粒生长、促进其无定形化的有效作用,从而在1.0~4.5 V电压区间内,CF_(x)电极可在0.1 C倍率下、经40次循环保持超300 mAh/g的可逆比容量,较无添加剂体系提升1倍以上。本研究深化了对CF_(x)电极转化反应行为与机制的认识,为Li/CF_(x)电池二次化提供了一种成本低廉、效果显著的调控策略,为未来高能量密度储能体系发展提供了新思路。
Fluorinated carbon(CF_(x))is a promising cathode material for lithium primary batteries due to its exceptionally high theoretical energy density compared to conventional reversible cathodes.Realizing rechargeable lithium/fluorinated carbon(Li/CF_(x))batteries,therefore,holds strategic significance for developing next-generation high-energy-density storage systems.However,progress remains limited by an incomplete understanding of the underlying reaction mechanisms and conversion dynamics strategies.This study systematically elucidates the lithium fluoride(LiF)deposition behavior during the CF_(x) conversion reaction.In the initial cycling stages,nanocrystalline LiF partially decomposes,contributing to reversible capacity.With continued cycling,however,LiF crystallites progressively coarsen,impeding decomposition kinetics and causing capacity fading.Based on this insight,a benzylamine-boron trifluoride complex is introduced as an electrolyte additive to regulate the conversion reaction process,thereby enabling the preliminary realization of rechargeable Li/CF_(x) batteries.Microscopy,spectroscopy,and elemental analyses confirm that the additive effectively suppresses LiF crystallization and promotes its amorphous transformation.Within a voltage window of 1.0-4.5 V and at a current rate of 0.1 C,the CF_(x) electrode delivers a reversible capacity exceeding 300 mAh/g after 40 cycles-more than twice that of pristine CF_(x).Overall,this study deepens the fundamental understanding of the CF_(x) conversion mechanism and presents a practical strategy to achieve reversible Li/CF_(x) chemistry,thereby laying the groundwork for next-generation high-energy-density energy storage systems.
作者
陈昊
喻嘉
崔艳华
施思齐
CHEN Hao;YU Jia;CUI Yanhua;SHI Siqi(School of Materials Science and Engineering,Materials Genome Institute,Shanghai University,Shanghai 200444,China;Institute of Electronic Engineering,China Academy of Engineering Physics,Mianyang 621000,Sichuan,China)
出处
《储能科学与技术》
北大核心
2025年第12期4689-4697,共9页
Energy Storage Science and Technology
基金
国家自然科学基金(22479093,U2030206,52474335)。
关键词
锂氟化碳电池
氟化锂沉积
苄胺三氟化硼
可逆比容量
Li/CF_(x)batteries
LiF deposition
benzylamine-boron trifluoride
reversible specific capacity
