Basicity-Engineered Graphite Fluoride Functionalization and Beyond: An Unusual Reaction between Ultraweak Nucleophile and Ultrastrong C-F Bonds

Graphite fluoride-launched graphene functionalization has attracted increasing interest in recent years. Highly basic nucleophiles are normally employed for ultrastrong C-F bonding. However, frequently, an appreciable majority of C-F units of graphite fluoride are reductively eliminated, leading to low functionalization degrees. It is hypothesized that graphite fluoride could likely be functionalized to a larger degree by lowering the basicity of the nucleophiles. Herein, ultraweakly basic NH3 center dot H2O is adopted as a nucleophile to react with extremely inert graphite fluoride, and the resulting reaction affords amino/hydroxyl cofunctionalized graphene (NH2-G-OH). As expected, the NH2/OH functionalization degree and the ratio of substituted C-F units to reduced ones reach high values of 0.34 and 1.62, respectively. Due to the dual energy-storage mechanisms of the electrochemical double-layer capacitance coupled with Faradaic pseudocapacitance, the NH2-G(8)-OH-based all-solid-state supercapacitors are flexible and robust and deliver state-of-the-art capacitive characteristics, while exhibiting high rate capability and electrochemical cycling stability. In addition, NH2/OH moieties remain highly reactive to be post-functionalized by versatile electrophiles, not only achieving an umpolung of graphite fluoride, but also enabling NH2-G(8)-OH a competitive alternative to monopolistic GO, and opening up an innovative pathway for development of high-performance graphene derivatives amenable to multifarious applications.