Lithium manganate composite material and preparation method thereof

A composite material, lithium manganese oxide technology, applied in the field of lithium-ion batteries, can solve the problems of high production cost agglomeration, uneven particle size distribution, large polarization and other problems in the synthesis process, and achieve good rate performance and cycle performance, uniform particle size, and source The effect of low price

Active Publication Date: 2016-09-07
SHENZHEN LIWEI LI ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a lithium manganate composite material and a preparation method thereof, aiming at solving the problems of high production cost, serious agglomeration, uneven particle size distribution, large particle size, and The problem of large internal resistance and large polarization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Take 1 L of high-magnesium-lithium-ratio natural brine lithium with a lithium content of 1100 mg / L, wherein the mass ratio of magnesium to lithium is 45.32, and adjust the pH to 6.0 with 0.02M disodium hydrogen phosphate-sodium dihydrogen phosphate buffer solution. Weigh 174gλ-MnO 2 The powder is treated in 0.01M dilute hydrochloric acid solution for 6 hours, filtered and placed in a container with a cover, injected with a high-magnesium-lithium-to-lithium ratio natural brine lithium prepared with a good pH value, closed the cover, shaken for 10 hours, filtered, washed, and heated at 100°C After drying for 6 hours, the λ-MnO 2 The lithium ion exchange rate is 34.7mg / g, and the magnesium ion exchange rate is 1.38mg / g. According to the measured amount of lithium and magnesium, add 4.72g of lithium carbonate, so that the molar ratio of lithium and magnesium: manganese molar ratio is 1:2, after mixing by ball milling for 3 hours, sintering in a muffle furnace at 550°C for ...

Embodiment 2

[0044] Take 1 L of high-magnesium-lithium-ratio natural brine lithium with a lithium content of 500 mg / L, wherein the mass ratio of magnesium to lithium is 36, and adjust the pH to 8.0 with 0.05M disodium hydrogen phosphate-sodium dihydrogen phosphate buffer. Weigh 174gλ-MnO 2 The powder is treated in 0.05 dilute sulfuric acid solution for 6 hours, filtered and placed in a container with a cover, injected with a high pH value of high-magnesium-lithium ratio natural brine lithium, closed the cover, shaken for 12 hours, filtered, washed, and baked at 120 ° C After drying for 4h, the λ-MnO 2 The lithium ion exchange rate is 30.9 mg / g, and the magnesium ion exchange rate is 2.07 mg / g. According to the amount of lithium and magnesium already contained, add 5.21g of lithium hydroxide so that the molar ratio of lithium and magnesium: manganese molar ratio is 1:2. After ball milling for 2 hours and mixing, it is sintered in a muffle furnace at 700°C for 10 hours to obtain doped lith...

Embodiment 3

[0047] Take 1 L of high-magnesium-lithium-ratio natural brine lithium with a lithium content of 1500 mg / L, wherein the mass ratio of magnesium to lithium is 51.3, and adjust the pH to 7.5 with 0.05M disodium hydrogen phosphate-sodium dihydrogen phosphate buffer solution. Weigh 174g λ-MnO 2 The powder is treated in 0.05 dilute nitric acid solution for 8 hours, filtered and placed in a container with a cover, injected with a high pH value of high-magnesium-lithium ratio natural brine lithium, closed the cover, shaken for 4 hours, filtered, washed, and baked at 150°C After drying for 2h, the λ-MnO 2 The exchange rate for lithium ion is 29.8 mg / g, and the exchange rate for magnesium ion is 2.76 mg / g. According to the amount of lithium and magnesium already contained, add 16.52g of lithium nitrate so that the molar ratio of lithium and magnesium: manganese molar ratio is 1:2, after ball milling for 4 hours, sintering in a muffle furnace at 680°C for 12 hours to obtain a doped type...

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PUM

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Abstract

The invention discloses a lithium manganate composite material and a preparation method thereof. The preparation method has the following advantages: 1) a natural lithium-bearing brine resource is comprehensively utilized as a lithium source, the usage amount of a refined lithium salt is reduced, and the material synthesis cost is substantially reduced; 2) the lithium source and a manganate source are uniformly distributed on an atomic level by an ion exchange method, a lattice matrix is easy to rearrange through short-range diffusion, the energy consumption is low during the synthesis process, a relatively low synthesis temperature and relatively short synthesis time are obtained, the grain distribution is uniform, and the polarization is reduced; 3) the constituent contents of lithium and magnesium are reasonably controlled by adjusting a pH value, lithium magnesium-doped type lithium manganate is prepared, the average valence state of manganate during the charge-discharge process is improved, a Jahn-Teller effect is effectively inhibited, and the cycle stability is improved; and 4) from the aspect of economic and environmental protection, the preparation method has more advantages than other schemes, and particularly, the preparation method has practical significance to extract lithium from a liquid-state lithium-bearing brine resource with a high magnesium-lithium ratio to synthesize a composite battery material.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium manganate composite material and a preparation method thereof. Background technique [0002] Lithium manganese oxide is one of the more promising lithium-ion cathode materials. Compared with lithium cobalt oxide and other cathode materials, lithium manganate has the advantages of abundant resources, low cost, no pollution, good safety, and good rate performance. It is an ideal However, its poor cycle performance and electrochemical stability greatly limit its wide application. Surface modification and doping can effectively modify its electrochemical performance, surface modification can effectively inhibit the dissolution of manganese and electrolyte decomposition; doping can effectively inhibit the Jahn-Teller effect during charge and discharge. The combination of surface modification and doping can undoubtedly further improve the electrochemical performance of t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/62H01M10/0525
CPCH01M4/364H01M4/505H01M4/628H01M10/0525Y02E60/10
Inventor 刘立君宋翠环
Owner SHENZHEN LIWEI LI ENERGY TECH CO LTD
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