Boron-Doped Graphene as a Promising Anode Material for Potassium-Ion Batteries with a Large Capacity, High Rate Performance, and Good Cycling Stability

Potassium-ion batteries (KIBs), as alternatives to lithium-ion batteries (LIBs), have attracted increasing attention due to the abundance of K in the Earth's crust. Here, using first-principles calculations, we have found that boron (B)-doped graphene is a promising anode material for KIBs. The studied B4C28 structure has a large specific capacity of 546 mAh/g, a small migration barrier of 0.07 eV, and a moderate potassiation voltage of 0.82 V to suppress the formation of a SEI layer. Moreover, B-doped graphene with a doping concentration of 12.5 at. % is metallic with good electron conductivity that can improve rate performance. Also, B doping makes the substrate electron deficient and results in significant charge transfer from K to the substrate, thus preventing K atoms from clustering, inhibiting dendrite growth, and leading to a good cycling stability.