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

Abstract

Layer-structured MoS 2 is regarded as a promising anode material for potassium ion batteries. Herein, MoS 2 nanosheets on N, P-codoping reduced graphene oxide (MoS 2 /N, P-rGO) have been successfully prepared via a facile two-step synthesis, where few-layered MoS 2 nanosheets are chemically bonded onto the surface of N, P-rGO. As an anode material, MoS 2 /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 MoS 2 and MoS 2 /rGO. These advanced performances outperform most of the reported anode materials for potassium ion batteries to date. Meanwhile, the K-storage reactions of MoS 2 /N, P-rGO have been disclosed through in-situ and ex-situ characterizations. The kinetics analysis confirms that K-storage of MoS 2 /N, P-rGO is predominant by pseudo-capacitance.

Understanding electrolyte salt chemistry for advanced potassium storage performances of transition‐metal sulfides

“…Figure shows the CV curves of MoS 2 /C using KFSI or KPF 6 in EC/DEC as the electrolyte in the first three cycles, showing similar cathodic/anodic peaks upon cycling. The redox peaks are in good agreement with previous reports 22,37 . The shallow cathodic/anodic peaks indicate the pronounced contribution to the total capacity from pseudocapacitive behaviors (Figure ).…”

“…To the best of our knowledge, the performances are also better than the ones reported (Figure 1F and Table S1). [38][39][40][41][42][43][44][45][46] The unprecedented rate performances may be due to the reduced interface resistance. This conclusion is directly supported by the EIS spectra of MoS 2 /C after three cycles (Figure S6A).…”

Ultrathin Metallic NbS2 Nanosheets with Unusual Intercalation Mechanism for Ultra‐Stable Potassium‐Ion Storage

“…The capacities of the first several cycles show a slight decline due to the irreversible reaction and gradual formation of SEI film, and then the capacities illustrate an increased tendency in the following several decades cycles mainly due to the complex process taking place in the electrochemical reactions such as the activated process of the electrode materials. [ 29,30 ] The reversible capacity is stabilized at 423.6 mAh g −1 after 500 cycles with high CE of ≈100%, showing high cyclic stability of NbS 2 nanosheets for PIBs. Besides, further studies of cycle performance for NbS 2 electrode at current densities of 0.5, 1 and 2 A g −1 reveal its high electrochemical reversibility and stability (Figure S8, Supporting Information).…”

Encapsulation of 2D MoS2 nanosheets into 1D carbon nanobelts as anodes with enhanced lithium/sodium storage properties

“…3,20 Through reducing the particle size of MoS 2 into the nanometer scale, the diffusion distance of Li + /Na + ions can be effectively shortened, thereby accelerating the reaction kinetics. Another strategy is to form MoS 2 /carbon-based nanocomposites with a special design to partly enhance the electrochemical properties of alkali metal ion batteries, such as MoS 2 /graphene networks, 21,22 CNTs@C@MoS 2 nanoarchitectures, 23 bowl-like C@MoS 2 nanocomposites, 24 hierarchical MoS 2 /N-doped carbon nanobelts, 25 MoS 2 @hollow carbon spheres, 26 etc. However, although this combination method can solve the problems of electrode conductivity and structural degradation, in most cases, the MoS 2 is usually loaded on the surface of the substrate, which is in direct contact with the electrolyte and suffers from drastic aggregation and unwanted side reactions during cycling.…”