Carbon materials have attracted much attention in many applications. Herein, high performance activated carbons (ACs) were synthesized from cheap coal raw material via a facile strategy by KOH activation. AC4T800t2 exhibited the higher BET surface area (2457 m² g⁻¹) and larger total pore volume (1.448 cm³ g⁻¹) among the as-synthesized ACs samples. The optimized material (AC4T800t2) displayed a specific capacitance as high as 384 F g⁻¹ at a scan rate of 5 mV s⁻¹ in 6 M KOH. The capacitance remained still at 279 F g⁻¹, even at a high scan rate of 200 mV s⁻¹, showing good rate performance. AC4T800t2 also showed excellent cycle performance (95% retention capacity after 5000 cycles) at a current density of 5 A g⁻¹. Furthermore, these ACs samples for CO₂ sorption were also investigated using a pressure swing adsorption (PSA) process. The CO₂ sorption behaviors of these samples were tested at 298.15 K in a pressure range of 0–1 MPa by the volumetric method. The Langmuir model provided good agreement with the experimental data (correlation coefficient above 0.99). The optimized material (AC4T800t2) showed a high CO₂ sorption capacity of 169.44 mL g⁻¹ (7.56 mmol g⁻¹) at 1 MPa, also a high CO₂ saturated uptake of 20.81 mmol g⁻¹ (91.56 wt%). Better CO₂ uptake is dependent on a larger micropore volume and higher specific surface area. In brief, the high performance AC samples have been synthesized for supercapacitors and CO₂ sorption.