Sulfur‐doped molybdenum phosphide as fast dis/charging anode for Li‐ion and Na‐ion batteries

Abstract

Summary The electrode materials with high rate capability are required to meet the ever‐demanding performance of rechargeable batteries. Herein, sulfur‐doped molybdenum phosphide (S:MoP) is prepared using (thio)urea‐phosphate‐assisted strategy and investigated as anode material for Li‐ and Na‐ion batteries. This approach provides the self‐doping of sulfur in MoP lattice that stabilizes the least stable oxidation state of phosphorus (P−3) of MoP through Mo/P–S bonds, enhances the electronic conductivity, and maximizes the Li‐/Na ions adsorption sites. The phase pure hexagonal S:MoP is obtained at 700°C (S:MoP‐7) and the complete reduction of phosphate is confirmed through X‐ray diffraction as well as X‐ray absorption spectroscopy. The presence of chemical bonding of Mo‐P/S and P‐S is detected by X‐ray photoelectron spectroscopy. S:MoP‐7 anode shows excellent rate capability where it delivers 112 mAh g−1 capacity at 12.8 C rate and high stability with 436 mAh g−1 capacity at 100th cycle at 0.1 C rate when tested in lithium‐ion batteries. The S:MoP‐7 as an anode exhibits high rate capability in sodium‐ion batteries and delivers 133 mAh g−1 capacity at 6.4 C rate and 307 mAh g−1 at 0.1 C rate at the 100th cycle. The high performance of the S:MoP‐7 electrode is attributed to the interconnected porous network, increased active sites for Li‐ and Na‐ions via S‐doping, and reduced charge transfer resistance as observed using electrochemical impedance spectroscopy.

Engineering Heterostructured Fe-Co-P Arrays for Robust Sodium Storage

“…Cyclic voltammetry (CV) sweeps of the Fe-Co-P anode in the initial three cycles are supplied in Figure 4a to detect the redox reactions upon (de)sodiation. During the first cathodic process, the broader reduction peak at 0.61 V contains two processes, one for the formation of the SEI layer and one for the conversion reaction process of FeP to Fe and Na 3 P and Co 2 P to Co and Na 3 P [27][28][29][30][31][32][33]. The oxidation peak at 2.27 V is predominantly caused by the desodiation course.…”

Nest-Like Molybdenum Diphosphide-Carbon Nanotube Nanocomposite for Lithium-Ion Storage

“…To satisfy the ever-growing demand for high-energy-density lithium-ion batteries (LIBs), new-generation anode materials with high capacity and long-term stability have been extensively explored. − In recent years, phosphorus-based materials, including metal phosphides (MPs) and elemental phosphorus with high theoretical specific capacity (500–1900 mA h g –1 for MPs and 2596 mA h g –1 for phosphorus) have been widely concerned. − ,− The highly delocalized electron and mixed anionic metal band in MPs induce a low oxidation state of metal and strong metal–phosphorus (M–P) covalent bonds. − MPs have better electrical conductivity (10 –12 –10 2 S m –1 for phosphorus and 10 –3 ∼ 10 6 S m –1 for MPs) and higher structural stability than elemental phosphorus, so the MP-based materials are promising anode materials for LIBs. ,,− Moreover, the formation of metallic nanocrystals within phosphorus matrices during charging/discharging cycles also provides additional electron transport pathways, which are required for high-rate anode. ,, Molybdenum phosphides (i.e., monophosphorus phase MoP and phosphorus-rich phase MoP 2 ) as low-cost catalysts for hydrogen evolution reaction and anode materials have been extensively explored. ,,− Molybdenum is an important element with a redox chemistry and better conductivity. The lithium-ion storage capacity of metal phosphides is proportional to the phosphorus content; ,,− thus, MoP 2 is a more attractive material for LIBs .…”

TiO2-coated MoP/phosphorus doped carbon nanorods for ultralong-life sodium ion batteries with high capacity

“…[7][8][9] MoP, with a nanorod structure, is a promising anode material. 10 However, it also encounters the challenge of volume changes that cannot be reversed during the reaction. Compounding with carbon-based materials is one of the effective strategies to address the above issues.…”