Lithium Titanate Composite Anode Double-Layer Coating
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Solution Overview
Problem
Lithium titanate-based lithium ion batteries face challenges due to the poor electric conductivity and electrochemical stability of spinel type lithium titanate as an anode active material, leading to electrolyte decomposition at low voltages, which decreases the battery's stability.
Innovation Solution
A lithium titanate composite material is developed with a double-layered structure comprising a carbon layer directly on the lithium titanate particles and an aluminum phosphate layer on the carbon layer, enhancing electric conductivity and stability by preventing electrolyte decomposition during lithium ion intercalation and deintercalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lithium titanate is used as anode active material, then high diffusion rate of lithium ions and high energy conversion efficiency are achieved, but poor electric conductivity and electrolyte decomposition at low voltage occur
Solution Approach 1:
The patent applies composite materials by combining lithium titanate particles with carbon material and aluminum phosphate to form a composite anode active material. The carbon material addresses the poor electric conductivity of lithium titanate, while the aluminum phosphate prevents electrolyte decomposition at low voltages, thus maintaining both high lithium ion diffusion rate and electrochemical stability.
Solution Approach 2:
The patent uses carbon material and aluminum phosphate as intermediary substances that mediate between the lithium titanate and the electrolyte. The carbon layer provides conductive pathways for electrons, while the aluminum phosphate layer acts as a protective barrier that prevents direct contact between the electrolyte and lithium titanate surface at low potentials, eliminating electrolyte decomposition.
2Use of energy by moving object
If lithium titanate is used as anode active material, then high energy conversion efficiency is achieved, but electrolyte decomposition decreases battery stability
Solution Approach 1:
The aluminum phosphate serves as an intermediary protective layer between the electrolyte and lithium titanate surface. This layer prevents the electrolyte from decomposing at the anode surface during charging and discharging cycles, eliminating the harmful effect while preserving the high energy conversion efficiency of lithium titanate.
Solution Approach 2:
The patent converts the potential harm of electrolyte decomposition into a benefit by using aluminum phosphate to create a stable interface. The aluminum phosphate layer that would otherwise be considered an additional material complexity actually protects the system by preventing electrolyte decomposition, thus converting a potential stability issue into a reliability enhancement.
3Reliability
If carbon material is coated on lithium titanate particles, then electric conductivity is improved, but electrolyte decomposition may still occur without aluminum phosphate layer
Solution Approach 1:
The patent segments the protective function into two distinct components: carbon material for improving electric conductivity and aluminum phosphate for preventing electrolyte decomposition. This segmentation allows each material to perform its specific function optimally without interfering with the other, ensuring both high conductivity and electrochemical stability.
Solution Approach 2:
The patent creates a composite structure with multiple functional layers: carbon material coating for conductivity enhancement and aluminum phosphate coating for electrochemical stability. This composite approach allows the material to simultaneously achieve improved electric conductivity through carbon while preventing electrolyte decomposition through aluminum phosphate protection.
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 composite material improves the electric conductivity and electrochemical stability of lithium titanate, allowing for safe and efficient lithium ion transfer at low discharge voltages, maintaining battery stability and performance.
Implementation Method 1
The lithium titanate is a semiconductor material having poor electric conductivity. The composite material improves the electric conductivity
Implementation Method 2
exhibits a high diffusion rate of lithium ions. allowing for safe and efficient lithium ion transfer
Implementation Method 3
The decomposition of the electrolyte results in a decrease of electrochemical stability of the lithium ion battery. maintaining battery stability and performance
Data Source
AI summary
A lithium titanate composite material includes a lithium titanate particle and a double layered structure coated on a surface of the lithium titanate particle. The double layered structure includes a carbon layer directly disposed on the surface of the lithium titanate particle, and an AlPO4 layer disposed on an outer surface of the carbon layer. The lithium titanate composite material, as an anode active material, can be applied to a lithium ion battery to increase its electrochemical stability.