Preparation method of lithium bis(oxalato)borate

Abstract

The invention relates to a preparation method of lithium bis(oxalato)borate. The preparation method comprises the following steps: A, completely dissolving an oxalate-containing compound and a boron source compound; B, dissolving lithium carbonate in excessive ethylene carbonate completely; and C, mixing a solution obtained in step A and a solution obtained in step B, and pumping the obtained mixture into a tubular reactor, performing a heating reaction to obtain a diethyl carbonate solution dissolved with lithium bis(oxalato)borate, evaporating under reduced pressure to obtain a lithium bis(oxalato)borate crude product, drying the lithium bis(oxalato)borate crude product, dissolving the crude product in an acetonitrile solution, performing dehydration treatment, performing evaporative concentrating on the obtained filtrate, carrying out cooling crystallization, carrying out solid-liquid separation, and drying to obtain purified lithium bis(oxalato)borate. The method has the followingadvantages: the process is simple, the cost is low, the yield is very high, the water content is effectively reduced, and the influence of water on the electrolyte is reduced; and the solvent is easyto recover, the repeated utilization rate is high, the treatment is simple, and the lithium bis(oxalato)borate with excellent properties and high purity can be prepared.

Description

Technical field [0001] The invention relates to the technical field of an electrolyte borate battery, in particular to a preparation method of lithium bisoxalate borate. Background technique [0002] Lithium-ion batteries have become one of the most eye-catching power sources due to their high energy density, long cycle life, high working voltage and many other advantages. They are widely used in computers, mobile phones, cameras, portable electronic equipment, and even in military, aerospace, etc. The development and optimization of lithium batteries has become one of the hot spots in the field of new energy. As an important part of lithium-ion batteries, electrolyte solutions play a pivotal role in lithium-ion batteries. Commercially commonly used lithium salt is LiPF 6 , Their thermal stability is very poor, storage performance and safety are not good, the compatibility with electrode materials is not very good, and they are very sensitive to water. Therefore, there is a lar...

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Problems solved by technology

[0004] (1) German patent 19829030C1 first reported LiB(C 2 o 4 ) 2 The synthetic method of different lithium salts, boron salts, oxalic acid or oxalate compounds constitute different synthetic routes respectively, and its reaction is liquid phase reaction, has water generation, and purity is lower;

[0005] (2) Xu et al. 3 ) 3 SiOOCCOOSi (CH 3 ) 3 and LiB(OCH 3 ) 4 Lithium bisoxalate borate was synthesized in the liquid phase as the raw material, and it was difficult to obtain the raw material, which increased the cost;

[0006] (3) Yu Bitao et al used the ball milling method in the invention patent 200510011555.7, the mixing was not uniform enough, the temperature was higher, and the solid phase method synthesized LiB(C 2 o 4 ) 2 , water is also generated, the yield is low, and the reaction conditions are complicated;

[0007] (4) Qiu Weihua et al synthesized LiB(C 2 o 4 ) 2 , also used the method of mechanical mixing, and there were also problems of insufficient mixing and low yield;

[0008] (5) Liao Huadong et al synthesized LiB(C 2 o 4 ) 2 , there is water generated, which is not conducive to industrial production;

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