Preparation And Application Of Nitrogen-doped Graphene Based High Energy Characteristic Composite Electrode Materials In Supercapacitors

With the fast development of science and economy, the use of renewable energy sources and the development of energy storage devices are becoming more and more improvement because of the increasing demand for energy and the severe environment pollution. Supercapacitor( SC) is a kind of energy storage device with many outstanding advantages of high power density, quickly charge-discharge, long cycling stability, which make SCs become a candidate for wearable electronic devices, communication devices, transportation, back up supply and large power equipment. But the SCs haven't been widely applied until now due to the low energy density. The development and study of electrode materials which possess both high energy and power characteristics is the key factor to solve the problem. The major target of this article is preparing excellent performance composite electrode materials with high specific and electron conductivity through the strategy that use the high electronic conducting materials as substrates and synthesize pseudocapacitance materials on the conducting substrates. The result are as follows:(1)Use the N-doped graphene as conducting substrates and synthesize cube NiCoO2 nanoparticles on the above substrates. Prepare flexible SCs devices with the as-prepared composite electrode materials. The results of XRD, SEM and TEM demonstrate that the NRGO-NiCoO2 has been successfully synthesized. The NRGONiCoO2 possesses specific capacitances of 508 F g-1 at the currents density of 0.5 A g-1. The fexible devices show capacitances of 58 F g-1 at the currents density of 0.5 A g-1. The flexible device exhibit good cyclic stability, maintaining 93%.(2)Heteroatom doping is an effective method to introduce pseudocapacitance mechanisms into graphene and improve the specific capacitance of graphene. The ? electrons in graphene can be activated by the electron-rich N and electron-deficient B. The boron and nitrogen co-doped graphene aerogel(BNRGA)has been synthesized and apply to SCs. The results of TEM and EELS demonstrate that the BNRGA has been successfully synthesized. The BNRGA possesses specific capacitances of 302 F g-1 at the currents density of 0.5 A g-1. The fexible all-solid-state devices show capacitances of 43 F g-1 at the currents density of 1 A g-1. The specific capacitance of fexible all-solid-state devices can be maintained at 97%.