Trace boron-doped porous carbon with a suitable amount of defects as anode for enhanced long-life potassium storage performance

Heteroatom doping is one of the common methods to modify structural defects and improve the electrochemical properties of carbonaceous material. A boron-doped three-dimensional porous carbon (BC) material with a defective structure was successfully prepared by a simple template and solid-phase method. Compared with pure carbon material, BC materials show superior anode electrochemistry for potassium-ion batteries (PIBs). Experimental evidence shows that the doping concentration of boron atoms affects the electrochemistry performance of the electrode material. The first charge-specific capacities were 231, 289, 445, and 325 mAh g−1 at 100 mA g−1 when the boron concentration was 0, 0.3, 0.4, and 0.5 at.%. As the current density came back to 200 mA g−1, the capacity immediately recovered to 182, 222, 361, and 246 mAh g−1. When the boron doping concentration was 0.4 at.%, this sample had a high reversible capacity of 283 mAh g−1 after 1000 cycles, and the coulomb efficiency approached 100 %. The interconnected porous structure provides channels for the penetration of the electrolyte and the transport of potassium ions. The stencil method gives the carbon material a large specific surface area and porous properties, and the boron doping introduces defects and active sites. The synergistic effect of these two results in an increased contribution to the capacitance control of the BC material. The cyclic stability of the BC material for high rate performance is further improved. So BC materials exhibit excellent capacity, cycle and rate performance in PIBs.