N, P-codoped graphene supported few-layered MoS₂ as a long-life and high-rate anode materials for potassium-ion storage

Layer-structured MoS₂ is regarded as a promising anode material for potassium ion batteries. Herein, MoS₂ nanosheets on N, P-codoping reduced graphene oxide (MoS₂/N, P-rGO) have been successfully prepared via a facile two-step synthesis, where few-layered MoS₂ nanosheets are chemically bonded onto the surface of N, P-rGO. As an anode material, MoS₂/N, P-rGO exhibits a high specific capacity (462.7 mAhdg^-1 at 100 mAdg^-1 over 200 cycles), outstanding rate capability (224.9 mAhdg^-1 at 20 Adg^-1), and excellent cycle life (236.6 mAhdg^-1 at 2 Adg^-1 after 7, 000 cycles), much better than those of MoS₂ and MoS₂/rGO. These advanced performances outperform most of the reported anode materials for potassium ion batteries to date. Meanwhile, the K-storage reactions of MoS₂/N, P-rGO have been disclosed through in-situ and ex-situ characterizations. The kinetics analysis confirms that K-storage of MoS₂/N, P-rGO is predominant by pseudo-capacitance.