Titanium Niobium Composite Oxide Battery Cycle Life
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Solution Overview
Problem
Conventional nonaqueous electrolyte secondary batteries with titanium-containing oxides as negative electrode active materials face significant cycle degradation issues, particularly in applications requiring long-term performance, such as in-vehicle and stationary power generation, where cycle life is measured in thousands of charge-discharge cycles, and the underlying causes of this degradation are not well understood.
Innovation Solution
Incorporating a titanium and niobium-containing composite oxide negative electrode and a nonaqueous electrolyte containing specific phosphate compounds, such as triphenylphosphine oxide, which stabilizes the electrolyte salt and inhibits side reactions, thereby improving cycle performance by preventing the formation of thick, ineffective solid electrolyte interface films and reducing irreversible capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional titanium-containing oxides are used as negative electrode active materials, then the battery can achieve practical use with reasonable cycle life, but the cycle performance deteriorates significantly in applications requiring thousands of charge-discharge cycles
Solution Approach 1:
The patent changes the chemical composition parameters of the negative electrode active material by incorporating both titanium and niobium elements in specific ratios (0.1-2.0 atomic ratio of Nb/Ti). This compositional parameter change creates a composite oxide structure that maintains electrochemical stability over thousands of cycles, resolving the contradiction between achieving practical cycle life and extending service life for long-duration applications.
Solution Approach 2:
The patent employs a composite material approach by creating a titanium-niobium composite oxide (Li2-x-yMxTi1-yNbyO3-δ) that combines the advantages of both elements. The composite structure provides enhanced structural stability and electrochemical performance, enabling the battery to maintain reliability over extended service periods of 10 years or more, thus resolving the contradiction between reasonable cycle life and extended service life.
2Duration of action of stationary object
If the battery operates for extended periods to meet 10-year service life requirements, then long-term stability is needed, but side reactions and solid electrolyte interface film formation increase, reducing capacity
Solution Approach 1:
The patent applies preliminary anti-action by using the phosphate compound (triphenylphosphine oxide) to preemptively suppress harmful side reactions between the electrolyte salt and negative electrode active material. This preliminary protective action prevents the formation of thick, ineffective solid electrolyte interface films that would otherwise consume lithium ions and reduce capacity over time, thereby maintaining energy efficiency throughout the extended service life.
Solution Approach 2:
The phosphate compound acts as an intermediary substance that mediates the interaction between the electrolyte salt and negative electrode active material. It forms a stable interface layer that prevents direct harmful reactions while allowing beneficial lithium ion insertion and extraction, thus reducing irreversible capacity loss and maintaining battery performance over the long service life period.
3Ease of manufacture
If conventional electrolyte compositions are used, then the battery can function with standard components, but side reactions occur between electrolyte salt and negative electrode active material, degrading cycle performance
Solution Approach 1:
The patent introduces a phosphate compound (triphenylphosphine oxide) as an intermediary additive in the electrolyte composition. This intermediary substance mediates the interaction between the electrolyte salt and negative electrode active material, suppressing harmful side reactions while maintaining manufacturing simplicity. The phosphate compound forms a protective interface that enhances cycle performance without significantly complicating the manufacturing process.
Solution Approach 2:
The patent modifies the electrolyte composition parameters by adding a specific phosphate compound at controlled concentrations. This parameter change transforms the electrolyte's chemical environment to be more compatible with the titanium-niobium composite oxide, reducing side reactions and improving cycle performance while maintaining ease of manufacture through straightforward compositional adjustment.
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 use of titanium and niobium-containing composite oxides with phosphate compounds in the electrolyte enhances the battery's cycle performance, extending its lifespan and maintaining discharge capacity over a longer period, particularly in high-cycle applications like in-vehicle systems.
Implementation Method 1
stabilizes the electrolyte salt and inhibits side reactions
Implementation Method 2
inhibits side reactions
Implementation Method 3
charged and discharged by the movement of lithium ions between positive and negative electrodes
Implementation Method 4
charged and discharged by the movement of lithium ions between positive and negative electrodes
Data Source
AI summary
According to one embodiment, a nonaqueous electrolyte battery includes a positive electrode, a negative electrode and a nonaqueous electrolyte. The negative electrode includes a titanium and niobium-containing composite oxide. The nonaqueous electrolyte includes at least one compound selected from compounds represented by the formulas (1) and (2).