Nb-Surface Ni-Rich Cathode Material for Lower Reaction Resistance
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries with high Ni content and low Co content face increased reaction resistance, which is not adequately addressed by existing technologies.
Innovation Solution
A lithium transition metal compound with a Ni content of 80-94 mol% and Nb content of 0.1-0.6 mol% is used, with a specific distribution state of Nb on the surface of particles, achieved through a method involving mixing composite oxides and baking under controlled temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the Ni content is increased to 80 mol% or more and Co content is reduced to 10 mol% or less, then the manufacturing cost is reduced and battery capacity is improved, but the reaction resistance of the battery increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the particle interior has high Ni content (80-94 mol%) for high capacity and low cost, while the particle surface contains Nb compound (0.1-0.6 mol%) to suppress reaction resistance. This spatial differentiation of composition allows simultaneous optimization of cost, capacity, and performance characteristics.
Solution Approach 2:
The patent uses composite materials by combining Ni-rich lithium transition metal compound with Nb compound to form a composite structure. The Nb compound acts as a surface coating or interfacial layer that modifies the surface properties while maintaining the bulk high-Ni composition, thereby achieving both low cost and low reaction resistance.
2Quantity of substance
If the Ni content is increased to 80 mol% or more, then the battery capacity is improved, but the reaction resistance of the battery increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the particle interior has high Ni content (80-94 mol%) for high capacity and low cost, while the particle surface contains Nb compound (0.1-0.6 mol%) to suppress reaction resistance. This spatial differentiation of composition allows simultaneous optimization of cost, capacity, and performance characteristics.
Solution Approach 2:
The patent uses composite materials by combining Ni-rich lithium transition metal compound with Nb compound to form a composite structure. The Nb compound acts as a surface coating or interfacial layer that modifies the surface properties while maintaining the bulk high-Ni composition, thereby achieving both high capacity and low reaction resistance.
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
This composition and processing method reduce the reaction resistance of the battery, enhancing its performance and capacity while maintaining economic viability.
Implementation Method 1
baking the mixture under an oxygen atmosphere in a baking furnace by increasing a temperature of the baking furnace with a temperature increasing rate at a temperature of greater than or equal to 450° C., and lower than or equal to 680° C. being in a range of greater than 3.5° C./minute and less than or equal to 5.5° C./minute
Implementation Method 2
baking the mixture under an oxygen atmosphere in a baking furnace by increasing a temperature of the baking furnace with a temperature increasing rate
Data Source
AI summary
A positive electrode active material to be used in a non-aqueous electrolyte secondary battery and containing a lithium transition metal compound which contains Ni in a proportion constituting 80-94 mol %, inclusive, relative to the total mole number of the metal elements other than Li, and also contains Nb in a proportion constituting 0.1-0.6 mol %, inclusive, relative thereto, the positive electrode active material being characterized in that the Nb amount n1 in a first sample solution obtained by adding 0.2 g of the lithium transition metal compound to a hydrochloric acid aqueous solution comprising 5 mL of pure water/5 mL of 35% hydrochloric acid, and the Nb amount n2 in a second sample solution obtained by immersing a filter used to filter the first sample solution in a fluonitric acid comprising 5 mL of 46% hydrofluoric acid/5 mL of 63% nitric acid satisfy the condition of 50%≤n1/(n1+n2)<75% when converted to molar quantities.