Trace Boron-Doped Porous Carbon with a Suitable Amount of Defects as Anode for Enhanced Long-Life Potassium Storage Performance

Abstract

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 are 231, 289, 445, and 325 mAh g-1 at 100 mA g-1 when the boron concentration is 0, 0.3, 0.4, 0.5 at.%. As the current density comes back to 200 mA g-1, the capacity immediately recovers to 182, 222, 361, and 246 mAh g-1. When the boron doping concentration is 0.4 at.%, this sample has a high reversible capacity of 283 mAh g-1 after 1000 cycles, and the coulomb efficiency approaches 100%. The structural defects caused by boron doping bring about more active sites, so BC materials exhibit excellent capacity, cycle and rate performance in PIBs.

Keywords: Porous carbon, boron doping, potassium-ion batteries, anode materials