SO2 Electrolyte Lithium Cell for Salt Solubility and Dendrite Control
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Solution Overview
Problem
Rechargeable battery cells with SO2-based electrolytes face issues such as dendrite growth, low solubility of conducting salts, and instability due to hydrolysis products, leading to reduced energy density, stability, and service life, as well as safety concerns from flammability and thermal runaway.
Innovation Solution
A rechargeable battery cell design featuring an SO2-based electrolyte with a specific conducting salt that forms a liquid solvate complex with SO2, enhancing solubility and oxidation stability, combined with a metallic lithium anode structure that prevents dendrite formation and is resistant to water, ensuring uniform lithium deposition and extended cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an SO2-based electrolyte is used, then oxidation stability and safety are improved, but solubility of conducting salts deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing specific additives (compounds with carbonyl groups, sulfones, or nitriles) that modify the solvent properties of SO2, thereby improving conducting salt solubility while maintaining oxidation stability
Solution Approach 2:
The patent creates a composite electrolyte system combining SO2 with specific additive compounds, where the additives work synergistically with SO2 to provide both high oxidation stability and improved conducting salt solubility
2Use of energy by moving object
If metallic lithium is used as active material, then energy density is improved, but dendrite growth and stability deteriorate
Solution Approach 1:
The patent introduces specific compounds as intermediary substances between metallic lithium and the electrolyte, which form protective interfaces that prevent dendrite growth while allowing lithium ion transport, thereby maintaining high energy density with improved stability
3Reliability
If conventional conducting salts are used, then conductivity is improved, but hydrolysis stability and service life deteriorate
Solution Approach 1:
The patent modifies the chemical parameters of conducting salts by selecting specific compounds (such as lithium tetrafluoroborate, lithium hexafluorophosphate, or lithium bis(trifluoromethanesulfonyl)imide) that have both high ionic conductivity and resistance to hydrolysis, thereby extending service life while maintaining conductivity
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 results in improved electrical performance, increased energy density, enhanced stability, and extended service life, with reduced self-discharge and improved safety due to the non-combustible nature of the electrolyte, while maintaining high conductivity and operational reliability across various temperatures.
Implementation Method 1
The electrolyte is based on SO2 and comprises at least one first conducting salt. The first conducting salt is dissolved in the electrolyte and forms a liquid solvate complex with the gaseous SO2
Implementation Method 2
At least one ion of the conducting salt (anion or cation) is sufficiently mobile in the electrolyte such that a charge transport between the electrodes, required for the functioning of the rechargeable battery cell, can take place through ionic conduction
Implementation Method 3
The active metal of a rechargeable battery cell is the metal whose ions within the electrolyte migrate to the negative or positive electrode when the cell is being charged or discharged and participate in electrochemical processes there
Implementation Method 4
The positive electrodes of lithium cells are designed as insertion electrodes. The term 'insertion electrode' in the sense of this disclosure refers to electrodes which have a crystal structure into which ions of the active material can be stored and removed during operation of the lithium cell
Implementation Method 5
The electrolyte is oxidatively electrochemically decomposed from a certain upper cell voltage of the rechargeable battery cell. This process often leads to an irreversible destruction of the electrolyte components
Implementation Method 6
Reductive processes can also decompose the electrolyte when falling below a certain cell voltage
Data Source
AI summary
This disclosure relates to a rechargeable battery cell comprising an active metal, at least one positive electrode having a discharge element, at least one negative electrode having a discharge element, a housing and an electrolyte, the negative electrode comprising metallic lithium at least in the charged state of the rechargeable battery cell and the electrolyte being based on SO2 and comprising at least one first conducting salt which has the formula (I),M being a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements, and aluminum; x being an integer from 1 to 3; the substituents R1, R2, R3 and R4 being selected independently of one another from the group formed by C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C6-C14 aryl and C5-C14 heteroaryl; and Z being aluminum or boron.