Enhancement of supercapacitors (SCs) with high-energy density and high-power density is still a great challenge. In this paper, a facile strategy for in situ anchoring of Co₃O₄ particles on N doped carbon cloth (pCoNCC) is reported. Due to the interaction of the doped N and Co₃O₄, the electrochemical performance improves significantly, reaching 1,940.13 mF·cm^-2 at 1 mA·cm^-2 and energy density of 172.46 µWh·cm^-2 at the power density of 400 µW·cm^-2, much larger than that without N doping electrode of 28.5 mF·cm^-2. An aqueous symmetric supercapacitor (ASSC) assembled by two pCoNCC electrodes achieves a maximum energy density of 447.42 µWh·cm^-2 and a highest power density of 8,000 µW·cm^-2. Utilizing such a high-energy storage ASSC, a digital watch and a temperature-humidity detector are powered for nearly 1 and 2 h, respectively. Moreover, the ASSC displays a superb electrochemical stability of 87.7% retention after 10,000 cycles at 40 mA·cm^-2. This work would provide a new sight to enhance active materials performance and be beneficial for the future energy storage and supply systems.