Sodium-Ion Battery Electrolyte Tuning for Gas-Suppressing Cathode Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transition metal oxides used in sodium-ion batteries generate gas due to reactions with ethylene carbonate in the electrolyte, leading to safety issues.
Innovation Solution
Adjust the content of metallic M elements in the positive electrode active substance and the composition of the electrolyte solution by incorporating vinylene carbonate, regulating ethylene carbonate and vinylene carbonate ratios to form a stable solid electrolyte interphase film, preventing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If transition metal oxide is used as positive electrode material to achieve high theoretical specific capacity, then energy storage capacity is improved, but gas generation occurs due to strong oxidizing property reacting with electrolyte
Solution Approach 1:
The patent introduces a protective coating layer as an intermediary between the transition metal oxide positive electrode and the electrolyte. This coating layer acts as a barrier that prevents direct contact and harmful oxidation reactions between the electrode material and electrolyte, thereby eliminating gas generation while preserving the high capacity benefits of transition metal oxide
Solution Approach 2:
The patent modifies the chemical composition parameters of the positive electrode material by doping with specific elements or forming composite structures. This parameter change reduces the strong oxidizing property of transition metal oxide while maintaining its high theoretical specific capacity, preventing gas generation through chemical modification rather than physical isolation
2Productivity
If ethylene carbonate is used in electrolyte solution to improve ion conductivity, then battery performance is enhanced, but gas generation is triggered through chemical reaction with positive electrode
Solution Approach 1:
The protective coating layer on the positive electrode serves as an intermediary that blocks the chemical reaction between ethylene carbonate and the electrode material. This allows ethylene carbonate to remain in the electrolyte for maintaining ion conductivity without causing harmful gas generation through direct contact with the positive electrode
Solution Approach 2:
The patent converts the potential harmful reaction between ethylene carbonate and the positive electrode into a beneficial outcome by using the reaction products or modified electrode surface to form a stable solid electrolyte interphase film. This film prevents further harmful reactions while maintaining the ion conductivity benefits of ethylene carbonate
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
Significantly reduces gas generation during cycling, enhancing the stability and performance of sodium-ion batteries by forming a robust SEI film on the positive electrode.
Implementation Method 1
the EC in the electrolyte solution chemically reacts with transition metal in a positive electrode active substance, generating gas and deteriorating the battery's performance. By doping the positive electrode active substance with metallic M element and adding vinylene carbonate (VC) to the electrolyte solution, the metallic M element can effectively promote VC to form a film preferentially on the positive electrode
Data Source
AI summary
Disclosed is a sodium-ion battery. By doping the positive electrode active substance with metallic M element and adding vinylene carbonate (VC) to the electrolyte solution, the metallic M element can effectively promote VC to form a film preferentially on the positive electrode. By regulating a mass content of ethylene carbonate in a total mass of the electrolyte solution, a mass content of vinylene carbonate in the total mass of the electrolyte solution, and a molar amount of the M element per mole of the positive electrode active substance, so that they satisfy 0≤w1≤30% and 0≤w1/(w2+d)≤5, the stability of the sodium-ion battery can be greatly improved, and the gas generation phenomenon can be reduced.