A method for preparing a hierarchically porous doped carbon material includes the steps of heating a mixture including an etching agent precursor and a pore-generating agent. The pore-generating agent is embedded in a matrix including a carbon source and a dopant source for simultaneously carbonizing the carbon source. The method further includes doping with the dopant and etching the pore-generating agent for obtaining the hierarchically porous doped carbon material. The hierarchically porous doped carbon material can form an electrode, and an energy storage device such as a supercapacitor can include such an electrode. The hierarchically porous doped carbon material can also help form an energy storage and conversion device such as a metal-air battery or a regenerative fuel cell.