Long term thermostable supercapacitor using in-situ SnO2 doped porous graphene aerogel

Thermally stable, long-cycle energy storages that are capable of operating at high temperatures are attracting much attention due to their importance in enhancing the thermal safety and durability of the electronic devices and further extending the application scope. Here, we develop high-performance and thermostable supercapacitors operating under high temperatures, which are fabricated by integrating SnO2-doped graphene aerogel electrodes and ionic liquid-based composite electrolytes. The tiny SnO2 nanoparticles are bonded chemically on the graphene sheets by in-situ formation without additional annealing, which initiates the electrochemical synergistic effect at high-temperatures. Also, the addition of fumed silica nanoparticles into the composite electrolytes not only improves the ionic conductivity of the polymer matrix but also enhances thermal stability. As a result, the excellent combination of the porous aerogel electrode and the composite electrolyte improves interfacial stability and enables the high-performance supercapacitor with a high specific capacitance of 541 F g(-1) and an energy density of 160 Wh kg(-1) at 125 degrees C. Further, the supercapacitor devices exhibit extremely long-term stability without significant capacitance loss after 10,000 cycles, even under high temperatures. This study provides a rational strategy for high-performance, long-cycle life, and high-temperature energy storage systems that supply electric energy in harsh environments.