Niobium-Doped Cathode Material for Stable High-Capacity Battery Paste
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current positive electrode active materials for non-aqueous electrolyte secondary batteries, particularly those containing niobium, face challenges in uniform distribution of niobium, leading to suboptimal battery characteristics and gelation issues during paste fabrication, which affects the battery's capacity and durability.
Innovation Solution
A lithium-nickel-manganese composite oxide with specific niobium distribution, where niobium is solid-dissolved inside primary particles and a controlled amount of lithium is eluted, is used to enhance battery characteristics and prevent gelation, achieved through a method involving mixing nickel-manganese composite hydroxide or oxide particles with a niobium compound and a lithium compound and firing at specific temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If niobium is added to lithium-metal composite oxide to improve battery characteristics, then thermal stability and capacity are improved, but uniform distribution of niobium is difficult to achieve
Solution Approach 1:
The patent applies preliminary action by pre-forming nickel-manganese composite hydroxide particles with controlled morphology and size before adding niobium compound and performing firing. This preliminary preparation ensures that niobium can be uniformly distributed during the subsequent firing process, resolving the contradiction between improving thermal stability through niobium addition and achieving uniform niobium distribution.
Solution Approach 2:
The patent employs parameter changes by controlling the particle size (3 μm or more and 20 μm or less) and morphology of nickel-manganese composite hydroxide particles, adjusting firing temperature (850°C or more and 1000°C or less), and optimizing the ratio of niobium compound to control niobium distribution. These parameter optimizations enable both improved thermal stability and uniform niobium distribution.
2Quantity of substance
If lithium content is increased to improve battery capacity, then charge and discharge capacity are improved, but gelation of positive electrode paste occurs during fabrication
Solution Approach 1:
The patent uses niobium compound as an intermediary substance that mediates between lithium content and paste stability. The niobium forms a protective layer or interacts with excess lithium to prevent gelation, allowing high lithium content (d≥1.0) to be maintained while avoiding paste gelation during electrode fabrication.
Solution Approach 2:
The patent creates a composite material system by combining lithium-nickel-manganese composite oxide with niobium compound, forming a multi-component composite (LidNi1-a-b-cMnaMbNbcO2+α) where niobium counteracts the gelation tendency caused by high lithium content, enabling both high capacity and ease of manufacture.
3Quantity of substance
If firing temperature is increased to improve battery characteristics, then capacity and output are improved, but production cost and energy consumption increase
Solution Approach 1:
The patent optimizes the firing temperature parameter to a specific range (850°C or more and 1000°C or less) that achieves the desired battery capacity and performance while minimizing energy consumption. This optimized temperature range ensures complete reaction and formation of lithium-niobium compound without excessive energy input, resolving the contradiction between improved capacity and reduced energy consumption.
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 approach results in improved battery characteristics, including high capacity, thermal stability, and reduced gelation of the positive electrode paste, facilitating industrial-scale production at a lower cost and ensuring high battery performance.
Implementation Method 1
niobium is solid-dissolved inside primary particles
Implementation Method 2
a controlled amount of lithium is eluted
Implementation Method 3
firing at specific temperatures
Data Source
AI summary
A positive electrode active material for non-aqueous electrolyte secondary battery containing a lithium-nickel-manganese composite oxide formed of secondary particles with a plurality of aggregated primary particles, in which the positive electrode active material is represented by a general formula (1): LidNi1−a−b−cMnaMbNbcO2+α, at least a part of niobium is solid-dissolved inside the primary particles, and an amount of lithium to be eluted into water when the positive electrode active material is immersed in water is 0.02% by mass or more and 0.10% by mass or less with respect to the entire positive electrode active material as determined by a neutralization titration method.