N‐Doped Porous Graphite‐Like Carbon Armored with Dense Amorphous Shell Through a Trojan Horse Strategy for High Performance Potassium‐Ion Battery Anode

Abstract N‐doped porous carbon materials are promising potassium‐ion battery anodes for overcoming the depressing rate performance and poor cycling stability issues associated with the oversized radius of K‐ion. However, the relatively low initial coulombic efficiency (ICE) as a result of porous structure and doped heteroatoms may limit the future application of potassium‐ion batteries. Herein, a novel N‐doped porous graphite‐like carbon armored with dense amorphous shell is synthesized through a Trojan horse strategy by etching and doping the carbon matrix from inside out using oxidized coal tar pitch coated C 3 N 4 as precursor. The N‐doped porous interior, which endows anode outstanding rate performance (156.5 mAh g −1 at 10 A g −1 ) and superior reversible capacity (412.3 mAh g −1 at 0.05 A g −1 ), is isolated from the electrolyte by the external dense shell to gain a high ICE of 62.6%. In addition, the integrated structure mitigates the risk of phase separation between the shell and core, thereby high‐current stability over 6000 cycles obtained. This work shed a new light on the fabrication of the well‐balanced carbon anodes to meet the demand of the future PIBs industry.