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 mAh·g−1 at 100 mA·g−1 over 200 cycles), outstanding rate capability (224.9 mAh·g−1 at 20 A·g−1), and excellent cycle life (236.6 mAh·g−1 at 2 A·g−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.