Bimodal Lithium Titanium Oxide Anode for High-Rate Battery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium titanium oxide anode active materials for lithium secondary batteries face challenges in achieving high rate capability and high electrode density while maintaining adhesion to the electrode, with existing materials either degrading charge and discharge characteristics or requiring excessive binders that reduce energy density.
Innovation Solution
A bimodal type anode active material comprising a mixture of first primary particles and secondary particles, with a weight ratio of 5:95 to 50:50, where the primary particles fill pores between secondary particles, improving adhesion and rate capability while reducing binder usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If LTO is composed of primary particles with small diameter (300 nm or less) to improve high rate capability, then charge and discharge characteristics are improved, but adhesion to electrode deteriorates and binder usage increases
Solution Approach 1:
The invention segments the particle system into two distinct size classes: primary particles (300 nm or less) for high rate capability and secondary particles (1-10 μm) for adhesion. This segmentation allows each particle type to fulfill its specific function without compromise, resolving the contradiction between speed and strength
Solution Approach 2:
The invention creates a composite particle system combining primary and secondary LTO particles in a bimodal distribution. The composite structure leverages the advantages of both particle sizes: small particles provide fast ion transport while large particles provide mechanical stability and adhesion, eliminating the need for excessive binder
2Strength
If secondary particles are formed by agglomeration of primary particles to improve adhesion, then adhesion to electrode is improved, but binder amount increases reducing energy density
Solution Approach 1:
The secondary particles serve as self-adhesive structures through their larger size and inherent surface properties, reducing dependence on external binder materials. The bimodal particle system allows secondary particles to provide mechanical anchoring to the electrode substrate without requiring proportionate amounts of binder, thus serving the adhesion function autonomously
Solution Approach 2:
The invention changes the particle size parameter to create secondary particles in the 1-10 μm range, which naturally provide improved adhesion characteristics. This parameter change reduces the specific surface area compared to purely nanoscale particles, thereby reducing the required binder amount while maintaining or improving adhesion
3Speed
If primary particles with large specific surface area are used to improve high rate capability, then charge and discharge characteristics are improved, but process limitations occur during slurry preparation
Solution Approach 1:
The invention segments the particle population into primary and secondary particles, where primary particles provide the high surface area needed for fast kinetics and secondary particles provide easier processability. This segmentation allows the slurry preparation process to handle the mixture more effectively than purely nanoscale particles while preserving the high rate capability benefits
Data Source
Figure 1~2
Figure 3
AI summary
Provided is an anode active material including a compound of Chemical Formula 1 below that may realize a high-density electrode and may simultaneously improve adhesion to the electrode and high rate capability, wherein the compound of Chemical Formula 1 includes first primary particles and secondary particles, and a ratio of the first primary particles to the secondary particles is in a range of 5:95 to 50:50: [Chemical Formula 1] LixMyOz where M is any one independently selected from the group consisting of titanium (Ti), tin (Sn), copper (Cu), lead (Pb), antimony (Sb), zinc (Zn), iron (Fe), indium (In), aluminum (Al), and zirconium (Zr) or a mixture of two or more thereof; and x, y, and z are determined according to an oxidation number of M.