Pulsed Thermal Shock Enables Deep Heteroatom Substitution and Substantial Reduction of Graphene

Developing efficient synthesis routes for heteroatom-doped graphene materials is of great significance for advancing high-performance energy storage systems. Herein, a rapid and scalable strategy for constructing B-substituted reduced graphene oxide (RGO-B) via pulsed rapid joule heating (PRJH) was demonstrated, enabling deep bulk-phase B incorporation and efficient thermal reduction with O removal. Zeta potential and Kelvin probe force microscopy (KPFM) analyses reveal that B substitution effectively modulates the electronic structure of graphene, resulting in a less negative surface and an increased work function, thereby significantly enhancing its rate capability. Remarkably, deeply heteroatom B-substituted graphene induces surface folding and interlayer spacing expansion, effectively increasing accessible active sites available for Li+ storage. Electrochemical tests demonstrate that the RGO-B electrode delivers a specific capacity of 415.5 mAh/g after 800 cycles at 0.5C, and maintains a capacity of 115.9 mAh/g after 20,000 cycles at an ultrahigh rate of 13C with a capacity retention exceeding 100%, exhibiting exceptional long-term cycling stability. These results highlight the great potential of RGO-B for ultra-long-cycle energy storage applications.