One-step ammonia activation of Zhundong coal generating nitrogen-doped microporous carbon for gas adsorption and energy storage

Development of porous carbon with both high surface area and high heteroatom doping has attracted considerable research attention in the fields of gas adsorption and electrochemical energy storage. However, cost-effective and scalable production strategies are still needed to accelerate industrial applications. In this study, we exploit a new type of nitrogen-doped microporous carbon by direct carbonization of abundant and low-cost Chinese Zhundong coal under ammonia atmosphere. As an adsorbent, the CO₂ adsorption capacity of this material can reach 3.71 mmol g⁻¹ at 0 °C and 1 bar with a high CO₂/N₂ selectivity of 22.83; the SO₂ adsorption capacity reaches 132.5 mg g⁻¹ at room temperature. Used as electrode materials, their specific capacitance is as much as 205 F g⁻¹ for supercapacitors at a low current density of 0.5 A g⁻¹ and maintains 129 F g⁻¹ at 50 A g⁻¹. The discharge capacity as a sodium ion battery anode at 200 mA g⁻¹ remains 190 mAh g⁻¹ even after 500 cycles. Together with their simple synthesis and inexpensive raw materials, these findings indicated that our N-doped carbon materials have great potential for practical application.