Gel Polymer Electrolyte Additives for Uniform SEI Formation
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Solution Overview
Problem
Semi-solid electrolytes in lithium-ion batteries face challenges in forming uniform solid-state electrolyte interphase (SEI) layers, which limits electrolyte decomposition and reversible lithium insertion/extraction, affecting battery performance and safety.
Innovation Solution
A gel polymer electrolyte composition including a polymer host, a liquid electrolyte, sulfolene additive, and ethylene carbonate, which forms a thin and uniform SEI layer on the electrode surface, enhancing lithium ion cycling and battery stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semi-solid electrolytes are used in lithium-ion batteries, then thermal safety and shelf life are improved, but the formation of uniform SEI layers is hindered
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing sulfolene additives (0.1-10 wt%) and ethylene carbonate additives (0.1-5 wt%) to the gel polymer electrolyte system. These compositional changes enable the formation of uniform SEI layers while preserving the thermal safety benefits of semi-solid electrolytes.
Solution Approach 2:
The patent creates a composite electrolyte system combining gel polymer matrix with specific additive compounds (sulfolene and ethylene carbonate). This composite approach leverages the thermal stability of the gel polymer while the added compounds facilitate uniform SEI layer formation, resolving the contradiction between safety and performance.
2Object-affected harmful factors
If semi-solid electrolytes are used in lithium-ion batteries, then non-volatility and non-flammability are achieved, but electrolyte decomposition and lithium insertion/extraction are limited
Solution Approach 1:
The patent adjusts the chemical composition by incorporating sulfolene and ethylene carbonate additives in specific concentrations. These parameter changes modify the electrolyte's interaction with electrodes, enabling efficient lithium insertion and extraction while preserving the non-flammable properties of the semi-solid matrix.
Solution Approach 2:
The sulfolene and ethylene carbonate additives act as intermediary substances that mediate between the semi-solid electrolyte matrix and the electrode surfaces. They facilitate lithium ion transfer and SEI layer formation without compromising the inherent safety advantages of the semi-solid electrolyte system.
3Device complexity
If gel polymer electrolyte is used, then separator and packaging requirements are reduced, but uniform SEI layer formation is not promoted
Solution Approach 1:
The patent modifies the gel polymer electrolyte composition by adding sulfolene (0.1-10 wt%) and ethylene carbonate (0.1-5 wt%). These compositional parameter changes enable uniform SEI layer formation on electrodes, compensating for the reduced structural separation provided by simpler packaging designs.
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 proposed gel polymer electrolyte composition improves battery rate capability, low-temperature discharge performance, high-temperature cycling, Columbic Efficiency, and reduces direct current resistance, leading to superior power and life performance.
Implementation Method 1
uniform solid-state electrolyte interphase (SEI) layers that are able to limit electrolyte decomposition and reversible lithium insertion/extraction of anode materials
Implementation Method 2
lithium ions may move from the positive electrode to the negative electrode during charging of the battery and in the opposite direction when discharging the battery
Data Source
AI summary
The present disclosure a gel polymer electrolyte for an electrochemical cell that cycles lithium ions. The gel polymer electrolyte includes a polymer host, a liquid electrolyte, and greater than or equal to about 0.1 wt. % to less than or equal to about 10 wt. % of a sulfolene additive. In certain variations, the gel polymer electrolyte also includes greater than or equal to about 0.1 wt. % to less than or equal to about 5 wt. % of an ethylene carbonate additive. The ethylene carbonate additive may be selected from the group consisting of: vinyl ethylene carbonate (VEC), fluoroethylene carbonate (FEC), vinylene carbonate, and combinations thereof. In each instance, the lithium electrolyte may include a first lithium salt, a second lithium salt that is distinct from the first lithium salt, and a third lithium salt that is distinct from the first lithium salt and the second lithium salt.