Li1+x(NiaCobMncMd)1−xO2 Electrode Material for Lithium-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries suffer from limited lifetime due to capacity loss after repeated cycles, which affects their cyclability and applicability in applications like automotive use, primarily due to mechanical stress caused by volume changes in electrode active materials during charging and discharging.
Innovation Solution
Development of an electrode active material with the formula Li1+x(NiaCobMncMd)1−xO2, where x is between 0 and 0.1, a is between 0.1 and 0.5, b is between 0.4 and 0.9, c is between 0 and 0.3, and d is between 0 and 0.1, with M selected from Al, B, Mg, W, Mo, Ti, and Si, and a+c+d>0, which exhibits reduced volume change and mechanical stress, improving cyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrode active materials are used, then manufacturing is simpler, but cyclability and lifetime are reduced due to volume changes during charging and discharging
Solution Approach 1:
The patent employs composite materials by combining multiple transition metals (nickel, cobalt, manganese) in specific ratios within the spinel structure, along with aluminum doping. This composite approach creates a material that maintains structural integrity during cycling while enabling lithium ion transport, thereby improving cyclability without excessive complexity
Solution Approach 2:
The patent systematically varies compositional parameters (nickel content 0.3-0.8, cobalt content 0.1-0.5, manganese content 0.1-0.4, aluminum doping 0.01-0.1) to optimize the balance between capacity and structural stability. By tuning these parameters, the material achieves reduced volume change during cycling while maintaining manufacturability
2Quantity of substance
If electrode active materials with high capacity are used, then charge density improves, but mechanical stress and capacity loss increase
Solution Approach 1:
The patent applies local quality by creating a core-shell like structure where the spinel lattice provides structural stability while lithium ion pathways enable high capacity. The aluminum doping locally reinforces the crystal structure at critical positions, reducing mechanical stress during volume changes while maintaining overall high charge density
Solution Approach 2:
The patent optimizes the ratio of transition metals to achieve the right balance: nickel provides high capacity (0.3-0.8), cobalt provides structural stability (0.1-0.5), and manganese provides mechanical strength (0.1-0.4). This parameter optimization enables simultaneous achievement of high charge density and mechanical stability
3Productivity
If lithium content is increased to improve capacity, then charge/discharge performance improves, but volume expansion and mechanical stress worsen
Solution Approach 1:
The patent precisely controls lithium content within the range of 1.01-1.05 in the formula Li1+x(Ni,Co,Mn)2-xAlxO4, avoiding excessive lithium that would cause volume expansion. This parameter control enables fast charge/discharge performance through sufficient lithium availability while limiting volume change through stoichiometric balance
Solution Approach 2:
The spinel composite structure with aluminum doping provides a framework that accommodates lithium insertion/extraction with minimal volume change. The composite nature of the material allows high lithium content for performance while the spinel framework constrains volume expansion
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 new electrode active material demonstrates improved cyclability and C-rate capacity behavior, leading to enhanced charge/discharge performance and extended battery life by minimizing volume changes during cycling.
Implementation Method 1
volume changes of the electrode active material, measured for example as change in crystallographic unit cell volume defined by unit cell axes dimensions a, b, and c and inclination angles of the axes in the unit cell α, β, and γ—in the course of charging and discharging
Implementation Method 2
a bigger change in volume of the electrode active material... may lead to mechanical stress in electrodes and thus contribute to a reduced cyclability
Data Source
AI summary
The present invention is related to an electrode active material for a lithium-ion battery of general formula (I): Li1+x(NiaCobMncMd)1−xO2 wherein x is in the range of from zero to 0.1, a is in the range of from 0.1 to 0.5, b is in the range of from 0.4 to 0.9, c is in the range of from zero to 0.3, d is in the range of from zero to 0.1, M is selected from Al, B, Mg, W, Mo, Ti, Si and Zr, with a+b+c+d=1 and a>c. In addition, the present invention is related to a method of manufacture of electrode active materials and to their use.