Lithium Titanium Oxide Negative Electrode Proton Substitution Control
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Solution Overview
Problem
Lithium titanium oxide in lithium secondary batteries experiences proton substitution when used with aqueous electrolytes, leading to decreased discharge capacity and cycle performance due to uneven charge-and-discharge reactions.
Innovation Solution
A secondary battery design incorporating a negative electrode with lithium titanium oxide having a degree of proton substitution between 0.01 and 0.2, along with water-based first and second electrolytes, to suppress proton substitution reactions and enhance discharge capacity and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an aqueous electrolytic solution is used in a lithium secondary battery, then the battery can be designed with water-based electrolytes, but proton substitution occurs in lithium titanium oxide leading to decreased discharge capacity and cycle performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the degree of proton substitution in lithium titanium oxide within the range of 0.01 to 0.2. This parameter optimization allows the material to maintain structural stability and electrochemical performance when used with aqueous electrolytes, thereby resolving the contradiction between electrolyte adaptability and cycle performance reliability
Solution Approach 2:
The patent uses composite materials by combining lithium titanium oxide with controlled proton substitution with water-based electrolytes. This composite approach enables the battery to achieve both the versatility of using aqueous electrolytes and the reliability of maintaining good cycle performance, as the proton-substituted lithium titanium oxide structure prevents excessive proton infiltration while allowing lithium ion transport
2Adaptability or versatility
If lithium titanium oxide is used as negative electrode active material, then the battery can operate with aqueous electrolytes, but uneven charge-and-discharge reactions occur due to proton substitution
Solution Approach 1:
The patent resolves this contradiction by changing the parameter of proton substitution degree to a specific range (0.01 to 0.2). This controlled parameter change ensures that the lithium titanium oxide maintains uniform charge-and-discharge reactions while remaining compatible with aqueous electrolytes, preventing both excessive proton substitution and insufficient electrolyte compatibility
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 approach allows for improved discharge capacity and cycle performance by preventing uneven charge-and-discharge reactions and enabling easy estimation of the state of charge (SOC) in the battery.
Implementation Method 1
a constituent element of a lithium titanium oxide is substituted by a proton (H+) in an aqueous electrolytic solution
Data Source
AI summary
According to one embodiment, a secondary battery (100) including a positive electrode (5), a negative electrode (3), a first electrolyte (9), and a second electrolyte (8). The negative electrode (3) includes a lithium titanium oxide having a degree of proton substitution of 0.01 to 0.2. The first electrolyte (9) includes water and in contact with the positive electrode (5). The second electrolyte (8) includes water and in contact with the negative electrode (3).