Fabrication of iodine/nitrogen co‐doped three‐dimensional porous reduced graphene oxide for high energy density supercapacitors

Abstract

Summary As an electrode for supercapacitor, the gravimetric specific capacitance of two‐dimensional layered graphene is theoretically superior to general porous carbon materials. However, the relatively low porosity and volumetric energy density of two‐dimensional graphene‐based electrode materials remain challenging for its practical application. Herein, iodine/nitrogen co‐doped three‐dimensional reduced graphene oxide (PGr) synthesized through the socking‐drying process and subsequent calcination is reported. In the presence of NH4I and KI, the obtained PGr containing 2.9 wt.% of I element and 3.15 wt.% of N element possesses highly interconnected three‐dimensional hierarchically porous network among the layered structure and possesses a high specific surface area of 622.5 m2·g−1. Moreover, the synthesized PGr exhibits exceptional electrical conductivity and excellent capacitive characteristics, delivering 268 F·g−1 of high gravimetric specific capacitance in a three‐electrode system in KOH (6.0 mol·L−1). Furthermore, symmetric supercapacitor assembled from the synthesized PGr shows 9.46 Wh·kg−1 of specific energy density when the power density is 600 W·kg−1 and its initial capacitance retains 97.5% after 10 000 cycles of charging and discharging at 10 A·g−1. In addition, the device utilizing ionic liquid as electrolyte delivers 32.9 and 46.2 Wh·kg−1 of specific energy density under 1.35 kW·kg−1 at 25°C and 1.85 kW·kg−1 at −50°C, respectively.

Application of N-Doped Carbon–Silicon Oxycarbide Based on POSS Synthesis in Lithium-Ion Batteries

“…The TGA and DSC curves of NSiOC (Figure S4) also show a 47.8% retention of the original mass, further indicating the approximate 50 wt % of N and C in the prepared NSiOC material. The existence of carbon coating and micropores could be beneficial in alleviating the volume expansion of silicon and the intercalation of lithium ions, − while nitrogen doping may enhance the conductivity of silicon-based composites and supply active sites by conjugating with the surrounding carbon atoms, which could in turn affect the performance of the thus-assembled LIBs. − …”

Unveiling the Supercapacitive Performance of B, P Dual‐Doped Graphene in Triple Redox Additives

“…N, F co-doped graphene Melamine and PTFE 230 F g À 1 @0.5 A g À 1 6 M KOH [65] N, I co-doped graphene Potassium iodide and ammonium iodide 268 F g À 1 @1 A g À 1 6 M KOH [66] N, Se co-doped graphene Urea and diphenyl selenide 302.9 F g À 1 @1 A g À 1 6 M KOH [67] B, P dual-doped graphene Boric acid and sodium phosphate 360…”