Preparation method of electrolytic manganese dioxide for positive material-lithium manganate of lithium battery

Abstract

The invention discloses a preparation method of electrolytic manganese dioxide for positive material-lithium manganate of a lithium battery. The method comprises the steps of (1) mixing manganese oxide ore powder with pyrite powder, and then adding the mixture and sulfuric acid into a leaching tank with continuous stirring according to a certain material ratio for reacting, thus obtaining a manganese sulfate solution, wherein the process reaction temperature is 85-90 DEG C and the reaction time is 3h-4h; (2) removing potassium; (3) purifying to remove impurities; (4) carrying out electrolysis; (5) dissolving; (6) carrying out high-temperature calcination to obtain the electrolytic manganese dioxide product. The electrolytic manganese dioxide prepared by the method is single in crystal form and has a pure beta type structure, so that lithium can be easily embedded in and removed out from the electrolytic manganese dioxide; the electrolytic manganese dioxide is very low in the content of impurities, so that the lithium manganate produced from the electrolytic manganese dioxide has excellent electrical property and safety performance.

Description

technical field [0001] The invention belongs to the technical field of electrolytic manganese dioxide production, in particular to a production method of electrolytic manganese dioxide for lithium manganese oxide, a cathode material of lithium batteries. Background technique [0002] With the development of science and technology, people put forward higher requirements on the performance of chemical power sources (batteries). The development of new energy research, especially battery materials is still an important strategic goal of today's scientific and technological development. The enhancement of environmental protection awareness makes people pay more and more attention to the development of electric vehicles, and this kind of battery should have large specific energy and specific power. Among many battery systems, lithium batteries stand out due to their advantages of high working voltage, high energy density and light weight, and are valued by countries all over the ...

AI Technical Summary

Problems solved by technology

Ordinary lithium manganate synthesized from EMD has a sodium ion content of about 500ppm, and impurities such as calcium, magnesium, and potassium are all about 300ppm, and its cycle performance is poor.

This is mainly due to the existence of MnO2 in the γ crystal form in EMD produced by general electrolytic manganese dioxide plants, but there are also miscellaneous items such as trimanganese tetraoxide and dimanganese trioxide, which are not conducive to lithium intercalation , In addition, the manganese dioxide content of ordinary EMD is only about 92%, mixed with more impurity phases, and the purity is poor

Therefore, it is difficult to separate Na, K, Ca, Mg, SO42- ions in lithium manganate prepared by existing EMD, especially when Na+ is too high, the residual ion-exchangeable sodium can be released through the discharge of the battery, which will cause the exchange of sodium and lithium in the electrolyte of the battery, because Na+It is larger than Li+, which will hinder the movement of Li+, seriously affecting the battery capacity and cycle performance, which is very important for the synthesis of high-performance lithium-ion battery cathode materials , there is also a large difference