The development of high-performance energy storage devices needs continuing efforts. To increase the energy/power density and flexibility of energy storage devices, we have proposed several unique approaches. (1) A hierarchical pore structure was proposed, in which different pores have different functions in supercapacitors (SCs). Then a hierarchical porous carbon materials with facilitated ion transport and good electrical conductivity was developed for SCs. (2) A common problem in SCs is that the specific capacity of electrode materials and the voltage window of electrolytes cannot be fully used. Benefiting from electrochemical charge injection to tune the electrode potential window, the energy density of SCs has significantly improved. (3) By using a commercially-available graphene material with high electrical conductivity developed by our group, a simple graphene membrane-sulfur structure was designed as cathode for Li-S batteries that show excellent performance. (4) A template-directed CVD was used to synthesize a 3D interconnected graphene framework (GF) that is flexible and has outstanding electrical and mechanical properties. By using the GF as a current collector on which Li₄Ti₅O₁₂ and LiFePO₄ were loaded as anode and cathode materials, a lightweight and flexible full lithium ion battery was fabricated. It has high-rate performance and energy density, and can be repeatedly bent without structural failure and performance loss.