富缺陷N/O共掺杂多孔炭框架材料作为高性能钾、钠离子电池负极材料OA北大核心CSTPCD

Carbon with its high electrical conductivity,excellent chemical stability,and structure ability is the most promising an-ode material for sodium and potassium ion batteries.We developed a defect-rich porous carbon framework(DRPCF)built with N/O-co-doped mesoporous nanosheets and containing many defects using porous g-C3N4(PCN)and dopamine(DA)as raw materials.We prepared samples with PCN/DA mass ratios of 1/1,2/1 and 3/1 and found that the one with a mass ratio of 2/1 and a carbonization temperature of 700 ℃ in an Ar atmosphere(DRPCF-2/1-700),had a large specific surface area with an enormous pore volume and a large number of N/O heteroatom active defect sites.Because of this,it had the best pseudocapacitive sodium and potassium ion stor-age performance.A half battery of Na//DRPCF-2/1-700 maintained a capacity of 328.2 mAh g-1 after being cycled at 1 A g-1 for 900 cycles,and a half battery of K//DRPC-2/1-700 maintained a capacity of 321.5 mAh g-1 after being cycled at 1 A g-1 for 1200 cycles.The rate capability and cycling stability achieved by DRPCF-2/1-700 outperforms most reported carbon materials.Finally,ex-situ Raman spectroscopy analysis result confirms that the filling and removing of K+and Na+from the electrochemically active defects are responsible for the high capacity,superior rate and cycling performance of the DRPCF-2/1-700 sample.