Prussian blue analogous positive material for sodium-ion batteries and preparation method of positive material

Abstract

The invention relates to a Prussian blue analogous positive material for sodium-ion batteries and a preparation method of the positive material and belongs to the technical field of sodium-ion batteries. The chemical composition of the positive material is Na2Ni0.4Co0.6Fe(CN)6. The preparation method of the positive material comprises the following steps: respectively dissolving nickel salt, cobalt salt and sodium ferrocyanide in water to prepare a nickel salt solution, a cobalt salt solution and a mother solution which are same in concentration; simultaneously adding the nickel salt solution and the cobalt salt solution into the mother solution, subsequently stirring in dark places at room temperature; then ageing at the room temperature; subsequently centrifuging and carrying out solid-liquid separation, firstly washing while centrifuging, subsequently washing by using absolute ethyl alcohol, and finally drying to prepare the positive material. The positive material has a plurality of characteristics of high capacity, high cycling stability and high coulombic efficiency and serves as novel low-cost and environmentally-friendly energy storage positive material for the sodium-ion batteries; the raw materials used by the method are widely distributed in the nature, are low in cost and are environmentally-friendly; the method is simple and is liable to control; the prepared positive material is stable in performance.

Description

technical field [0001] The invention relates to a Prussian blue analog positive electrode material for a sodium ion battery and a preparation method thereof, specifically, the chemical composition of the positive electrode material is Na 2 Ni 0.4 co 0.6 Fe(CN) 6 , belongs to the technical field of sodium ion batteries. Background technique [0002] The excessive exploitation and utilization of traditional fossil energy has not only caused serious environmental pollution, but also brought about an energy crisis. Clean renewable energy, such as: wind energy, solar energy, tidal energy, etc., has become the key to solving the problem, and thus has received widespread attention. In fact, due to the periodicity and instability of these energy sources, they cannot be directly connected to the grid for human use. They can only be used after they are stored by energy storage devices. Secondary batteries are currently popular energy storage systems, among which, lithium-ion batt...

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Problems solved by technology

Prussian blue analogs (Na 2 NiFe(CN) 6 ) material has 65mAh g in water system battery -1 97% of the initial capacity can be maintained after 500 cycles, and 61mAh g can still be maintained at a high current density of 10C -1 capacity (Wu, X., et al., A low-cost and environmentally benign aqueous rechargeable sodium-ion battery based on NaTi 2 (PO 4 ) 3 -Na 2 NiFe(CN) 6 intercalation chemistry.Electrochemistry Communications,2013.31:p.145-148.); The Prussian blue analog Na 2 NiFe(CN) 6 The only downside to the material is the lower capacity

While the Prussian blue analog Na 2 CoFe(CN) 6 The material has more than 120mAh g -1 capacity, but its cycle performance is poor (Qian Jiangfeng et al., Na x m y Fe(CN) 6 (M=Fe, Co or Ni): A Novel Cathode Material for Sodium-ion Batteries. Electrochemistry, 2012(02): pp. 108-112)

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