Nano-Structured Spherical Cathode Materials for High Energy Density Li-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium-ion batteries for electric vehicles require higher energy density and power capability, which is hindered by the lack of cathodic materials with high specific capacity, operating voltage, and rate capability due to inadequate ionic and electronic conductivity.
Innovation Solution
Development of nano-sized structured positive active materials with specific metal oxide compositions and morphologies, such as Li1+α(NixCoyMnz)1−tMtO2−dRd, achieved through a process involving acidic and basic solution combination, precipitation, and calcination, resulting in spherical secondary particles with enhanced packing density and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional cathodic materials are used, then manufacturing simplicity is maintained, but energy density and rate capability are insufficient
Solution Approach 1:
The cathodic material is segmented into hierarchical structures with primary particles (1-100 nm) aggregated into secondary particles (1-20 μm). This segmentation increases the surface area for lithium-ion insertion/extraction while maintaining structural integrity, thereby improving energy density and rate capability without excessive complexity
Solution Approach 2:
Different regions of the material structure are optimized for different functions: primary particles provide high surface area for rapid lithium-ion diffusion (improving rate capability), while secondary particles provide structural stability and electron conduction pathways (maintaining manufacturing feasibility). This local optimization resolves the contradiction between performance and complexity
2Reliability
If larger particle sizes are used, then manufacturing ease is maintained, but ionic conductivity and lithium-ion diffusion are insufficient
Solution Approach 1:
The material is divided into primary particles of 1-100 nm that aggregate into secondary particles of 1-20 μm. The nano-scale primary particles ensure rapid lithium-ion diffusion and high ionic conductivity, while the micro-scale secondary particles are easier to handle and process. This hierarchical segmentation resolves the contradiction between ionic conductivity and manufacturing precision
Solution Approach 2:
The particle size parameters are precisely controlled within specific ranges: primary particles at 1-100 nm for high ionic conductivity, and secondary particles at 1-20 μm for manufacturability. This parameter optimization balances the competing requirements of ionic conductivity and manufacturing precision
3Use of energy by moving object
If higher specific capacity materials are used, then energy density improves, but electronic conductivity and rate capability deteriorate
Solution Approach 1:
High specific capacity materials are segmented into nano-scale primary particles (1-100 nm) that aggregate into micro-scale secondary particles (1-20 μm). The nano-scale segmentation provides numerous surface sites for rapid lithium-ion insertion/extraction (improving rate capability), while the aggregated structure maintains electron conduction pathways (preserving electronic conductivity). This resolves the contradiction between specific capacity and rate capability
Solution Approach 2:
The hierarchical structure creates a composite morphology where primary particles provide high surface area for fast kinetics and secondary particles provide structural stability and electron conduction. This composite architecture enables the material to simultaneously achieve high specific capacity and high rate capability
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 nano-sized structured materials exhibit increased specific capacity, energy density, rate capability, and cycling performance, effectively addressing the energy and power demands of electric vehicles.
Implementation Method 1
combining the acidic solution with the basic solution; and precipitating a nano-sized structured precursor from the combined acidic and basic solutions
Implementation Method 2
a process involving acidic and basic solution combination, precipitation, and calcination, resulting in spherical secondary particles with enhanced packing density and conductivity
Data Source
AI summary
Nano-sized structured dense and spherical layered positive active materials provide high energy density and high rate capability electrodes in lithium-ion batteries. Such materials are spherical second particles made from agglomerated primary particles that are Li1+α(NixCoyMnz)1−tMtO2−dRd, where M is selected from can be Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, Zr, or a mixture of any two or more thereof, R is selected from F, Cl, Br, I, H, S, N, or a mixture of any two or more thereof, and 0≦α≦0.50; 0<x≦1; 0≦y≦1; 0<z≦1; 0≦t≦1; and 0≦d≦0.5. Methods of preparing such materials and their use in electrochemical devices are also described.