Lithium Cobalt Titanium Oxide Cathode Material for Battery
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Solution Overview
Problem
Current rechargeable lithium batteries face challenges in achieving high capacity and cycle-life while maintaining high power characteristics, particularly in the development of positive active materials that can efficiently intercalate and deintercalate lithium ions.
Innovation Solution
A positive active material represented by the compound LixCo1−yTiyO2, where 1<x≤1.1 and 0.02≤y≤0.05, is developed, which is synthesized by mixing lithium, titanium, and cobalt-containing materials and heat-treating them at temperatures above 1000°C, resulting in a compound with improved initial charge capacity and low phase transition voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional lithium cobalt composite metal oxides are used as positive active materials, then high power characteristics are achieved, but initial charge capacity and cycle-life are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the positive active material. Specifically, it uses a compound with formula LixCo1-yTiyO2 where x>1 ( lithium excess) and y ranges from 0.01 to 0.06 (titanium substitution). This compositional parameter modification enables the material to achieve both high power characteristics and improved cycle-life, resolving the contradiction between power and reliability.
Solution Approach 2:
The patent employs composite materials by creating a lithium cobalt titanium oxide compound where titanium substitutes for cobalt in the crystal structure. This composite approach combines the high power characteristics of lithium cobalt oxide with the enhanced stability and cycle-life properties introduced by titanium substitution, simultaneously achieving both improving features.
2Quantity of substance
If titanium substitutes cobalt in lithium cobalt oxide, then initial charge capacity increases, but manufacturing complexity increases
Solution Approach 1:
The patent merges the synthesis of multiple components into a single step by co-precipitating lithium, cobalt, and titanium salts together to form a precursor mixture, which is then sintered in one heat treatment process. This merging approach increases initial charge capacity through titanium substitution while avoiding the need for multiple separate manufacturing steps, thereby limiting the increase in manufacturing complexity.
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 solution provides a rechargeable lithium battery with enhanced initial charge capacity, high cycle-life characteristics, and improved stability, effectively addressing the limitations of conventional lithium cobalt composite metal oxides by incorporating titanium to substitute cobalt, thereby increasing the battery's capacity and power performance.
Implementation Method 1
heat-treating them at temperatures above 1000°C
Data Source
AI summary
Disclosed are a positive active material for a rechargeable lithium battery including a compound represented LixCo1−yTiyO2, wherein 1<x≤1.1 and 0.02≤y≤0.05; a method of preparing the same; and a rechargeable lithium battery including the same.