Sodium ion total battery and preparation method thereof

Abstract

The invention discloses a preparation method of a sodium ion total battery. The preparation method comprises the steps of S1 uniformly mixing a Na3Fe2 (SO4) 3F / C positive electrode material, a conductive carbon material and a binder in a solvent, coating an aluminum foil current collector with the mixture, and carrying out drying treatment to obtain a positive electrode plate; S2 uniformly mixinga hard carbon negative electrode material, a conductive carbon material and a binder in a solvent, coating a copper foil current collector with the mixture, and carrying out drying treatment to obtaina negative electrode plate; and S3 assembling the positive electrode plate and the negative electrode plate by adopting a diaphragm, a gasket, an elastic piece, a positive pole shell and a negative pole shell, adding an electrolyte, and packaging to obtain the sodium ion total battery. According to the sodium ion total battery disclosed by the invention, the positive electrode is prepared from the Na3Fe2 (SO4) 3F / C positive electrode material, so that the sodium storage specific capacity can be ensured, meanwhile, the cycling stability and the rate capability are greatly improved; the sodiumstorage electrochemical performance is obviously superior to that of a pure-phase NaxFly (SO4) z material; and compared with other sodium-containing layered transition metal oxides, polyanionic vanadium-based phosphates and other positive electrode materials, the positive electrode material has obvious advantages in the aspects of working potential and energy density.

Description

technical field [0001] The invention relates to the technical field of sodium ion batteries, in particular to a sodium ion full battery with low cost, high working potential and high energy density and a preparation method thereof. Background technique [0002] With the rapid development of pure electric vehicles and large-scale energy storage systems, the demand for lithium-ion batteries as a core component has increased dramatically. However, the content of lithium in the earth's crust is very limited, and the recycling and reuse of lithium-ion batteries cannot be realized efficiently, resulting in a continuous increase in the sales price of lithium-ion batteries, which affects the promotion and promotion of new energy electric vehicles and energy storage power stations. application. [0003] Sodium-ion batteries have a very similar working principle to lithium-ion batteries, using the reversible intercalation and intercalation of sodium ions in the positive and negative ...

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Problems solved by technology

However, this method applies to Na x Fe y (SO 4 ) z In material modification technology, due to Na x Fe y (SO 4 ) z The very low preparation temperature of the material, generally lower than 450°C, leads to the following problems: 1. Insufficient carbonization of the organic carbon source, which makes the prepared surface carbon coating layer itself low in electrical conductivity, which is not conducive to the improvement of Na x Fe y (SO 4 ) z The electrical conductivity of the material plays little role

Therefore, the irreversible oxidation of Fe elements and the formation of impurity phases during its preparation cannot be effectively suppressed, as well as the structural collapse caused by phase transition or reaction stress enrichment during electrochemical sodium storage.

Therefore, this scheme has no significant effect on improving the electrochemical performance of polyanionic sodium ferric sulfate cathode materials, and fails to obtain ideal sodium storage capacity, cycle stability and high rate performance.

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