An optimized nanostructure design for high-power, high-energy lithium-ion batteries and supercapacitors is realized by fabricating a nanocomposite with highly dispersed nanoparticles of active materials in a nanoporous carbon matrix. A nano-LiFePO4/nanoporous carbon matrix nanocomposite forms a bridge between a supercapacitor and a battery electrode and offers a reasonable compromise between rate and capacity.