Carbonate Precipitation Process for Lithium-Ion Battery Cathode
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Solution Overview
Problem
The existing processes for producing cathode active materials for lithium ion secondary batteries often result in ununiform particle size and shape, leading to voids and poor cycle characteristics, especially when the manganese proportion is lowered to increase discharge capacity.
Innovation Solution
A process involving the controlled mixing of sulfates and carbonates in aqueous solutions to achieve specific proportions of manganese, nickel, and cobalt, followed by firing with lithium carbonate, to produce a carbonate compound with uniform particle size and shape, thereby enhancing the cycle characteristics of the cathode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the proportion of Mn is lowered to increase discharge capacity, then the discharge capacity increases, but the particle size and particle shape become ununiform and voids are formed
Solution Approach 1:
The patent applies preliminary action by controlling the Mn proportion in the sulfate solution before the precipitation reaction. By setting the Mn proportion to 65 mol% or more in the sulfate solution at the start of mixing, the process ensures uniform particle formation during precipitation, preventing the ununiformity and void formation that would otherwise occur when Mn content is reduced for higher discharge capacity.
Solution Approach 2:
The patent uses parameter changes by specifically controlling the Mn proportion parameter in the sulfate solution to be 65 mol% or more. This parameter control during the precipitation process enables the formation of cathode active material with uniform particle size and shape, even when the final Mn content in the product is reduced to increase discharge capacity.
2Quantity of substance
If the proportion of Mn is lowered to increase discharge capacity, then the discharge capacity increases, but voids are easily formed in the cathode active material
Solution Approach 1:
The patent applies preliminary action by controlling the Mn proportion in the sulfate solution before the precipitation reaction. By setting the Mn proportion to 65 mol% or more in the sulfate solution at the start of mixing, the process ensures uniform particle formation during precipitation, preventing the ununiformity and void formation that would otherwise occur when Mn content is reduced for higher discharge capacity.
Solution Approach 2:
The patent uses parameter changes by specifically controlling the Mn proportion parameter in the sulfate solution to be 65 mol% or more. This parameter control during the precipitation process enables the formation of cathode active material with uniform particle size and shape, even when the final Mn content in the product is reduced to increase discharge capacity.
3Ease of manufacture
If conventional mixing process is used, then the production process is simple, but the cycle characteristics deteriorate quickly
Solution Approach 1:
The patent applies preliminary action by controlling the Mn proportion in the sulfate solution before the precipitation reaction. By setting the Mn proportion to 65 mol% or more in the sulfate solution at the start of mixing, the process ensures uniform particle formation during precipitation, preventing the ununiformity and void formation that would otherwise occur when Mn content is reduced for higher discharge capacity.
Solution Approach 2:
The patent uses parameter changes by specifically controlling the Mn proportion parameter in the sulfate solution to be 65 mol% or more. This parameter control during the precipitation process enables the formation of cathode active material with uniform particle size and shape, even when the final Mn content in the product is reduced to increase discharge capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process produces a cathode active material with improved uniformity and cycle characteristics, leading to a lithium ion secondary battery with sustained discharge capacity and voltage stability.
Implementation Method 1
mixing the sulfate (A) and the carbonate (B) in the form of aqueous solutions to precipitate a carbonate compound
Implementation Method 2
the pH of the mixed solution in a mixing tank is maintained at from 7 to 12
Implementation Method 3
mixing the carbonate compound obtained by the process as defined in any one of the above (1) to (6) and lithium carbonate, followed by firing at from 500 to 1,000° C.
Data Source
AI summary
To provide a carbonate compound and a cathode active material, whereby a lithium ion secondary battery having excellent cycle characteristics can be obtained.A process for producing a carbonate compound, which comprises mixing a sulfate (A) comprising a sulfate comprising a sulfate of Mn and a sulfate of Ni, or a sulfate comprising a sulfate of Mn, a sulfate of Ni and a sulfate of Co, and a carbonate (B) which is at least one carbonate selected from the group consisting of sodium carbonate and potassium carbonate, in the form of aqueous solutions and controlling the proportion of Mn to the total of Ni, Co and Mn contained in the sulfate (A) to be higher than 65 mol % at the initiation of the mixing, to precipitate a carbonate compound having a proportion of Mn of from 33.3 to 65 mol %, a proportion of Ni of from 17.5 to 50 mol % and a proportion of Co of from 0 to 33.3 mol % to the total of Ni, Co and Mn in the total average composition. A process for producing a cathode active material, which comprises mixing the carbonate compound obtained by the above process and lithium carbonate, followed by firing at from 500 to 1,000° C.