Synthesis of Metal Oxides@C (Metal = Ni, Fe) Based Prussian Blue Analogs as a High-performance Anode Material for Lithium-ion Battery

Abstract

Ni 3 [Fe(CN) 6 ] 2 nano-cubic precursors were prepared by chemical coprecipitation at room temperature with nickel acetate and potassium ferricyanide as raw materials. The corresponding NiFe 2 O 4 -NiO@C composites with excellent crystallization were prepared by two-stage oxidation at low temperature. The microstructure and electrochemical behavior of the materials showed that the Prussian blue analog was transformed into metal oxide while the carbon coating was maintained in the twostage oxidation at low temperature. The existence of the carbon coating reduces the charge transfer impedance to 31.5 Ω. At the current density of 500 mA/g, the reversible capacity of 632.7 mAh/g is maintained after 500 cycles. At the same time, carbon cladding can also enhance the role of pseudocapacitance in the material. At the scanning rate of 0.1 mV/s, the pseudocapacitance account for 54.4% of the total discharge capacity, which is significantly higher than that of uncoated materials.

Fe-Doped Zinc Oxide Rods Coated with Nanometer-Thick N-Doped Carbon for Lithium-Ion Storage

“…Lithium-ion batteries (LIBs) have been a primary power storage device applied in the portable electronic devices and electric vehicles in the past decades. − However, the unsatisfied theoretical capacity of 372 mAh g –1 for commercial graphite anode greatly restricts the development of high energy-density LIBs. , Much attention has been focused on exploring promising anode materials with high specific capacities and excellent energy densities, such as conversion mechanism-based transition metal oxides (TMOs), intercalation-related transition metal sulfides (TMSs), and alloy-based materials with high theoretical specific capacity (>600 mAh g –1 ). − Zinc oxide (ZnO), one of TMOs, has been considered a promising anode material due to its high theoretical capacity (987 mAh g –1 ), eco-friendliness, and abundant resources. , However, poor electronic conductivity and severe volume effect during the Li + insertion/extraction process would reduce the cycle stability and cycle life of ZnO anode. Hierarchical nano/microstructure design, heteroatom doping, , vacancies, and hybriding with nitrogen-doped carbon − have been proven to be effective to improve the electrochemical property of TMOs.…”