“Nanotechnology is an idea that most people simply don’t believe” but its uses in the field of medicine, electronics, fuel cells, batteries, sensors, or energy storage left everyone spellbound. In the twenty-first century, energy storage and its conversion remains the greatest challenge in front of scientific community. In order to store more energy, we need to develop novel electrodes that use material with high specific surface area as well as low resistance. However, most of the researchers round the globe have either developed or focused on developing electrodes that rely on electrochemical double layer capacitance (EDLC) mechanism for charge storage. This chapter contains all the latest modifications done in carbon-based nanomaterials (such as CNTs, graphene, etc.) to enhance their charge storage capacity along with recently developed binary nanocomposites (CNT/metal oxide or CNT/conducting polymers) that uses both EDLC as well as pseudocapacitance phenomenon to show maximum possible specific capacitance values reported till date.