TMCCC Cell Electrolyte With Dinitrile Additive for Fast Deep Discharge

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Solution Overview

Problem

Secondary electrochemical cells with transition metal cyanide coordination compound (TMCCC) materials face degradation issues due to parasitic reactions, particularly when operating within a narrower voltage window, which reduces energy utilization and increases internal resistance, and existing electrolytes with different solvents compromise ionic conductivity and high-rate capability.

Innovation Solution

A liquid electrolyte system incorporating a mononitrile solvent and a dinitrile additive, such as acetonitrile with succinonitrile or adiponitrile, is used to enhance the lifetime of TMCCC-based electrochemical cells by suppressing parasitic reactions and maintaining high ionic conductivity, allowing for fast discharge to extreme depths without degrading performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a narrower voltage window is used to diminish parasitic reactions, then cell degradation is reduced, but energy utilization is significantly diminished

Engineering Contradiction:

Improvecell degradation resistanceVSAvoidenergy utilization

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte by introducing a dinitrile additive with specific molecular structure and properties. This additive modifies the electrolyte's interaction with electrode materials, allowing the cell to operate at higher voltages without excessive parasitic reactions. The dinitrile additive concentration is optimized to balance energy utilization and degradation resistance, enabling broader voltage windows while maintaining cell stability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a different liquid electrolyte is substituted to reduce parasitic reactions, then parasitic reaction rate is reduced, but electrolyte conductivity decreases which lowers maximum charge and discharge power

Engineering Contradiction:

Improveparasitic reaction resistanceVSAvoidmaximum charge and discharge power

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent creates a composite electrolyte system by combining a base liquid electrolyte with a dinitrile additive. This composite formulation leverages the high conductivity of conventional electrolytes while the dinitrile component suppresses parasitic reactions. The synergistic interaction between the base electrolyte and dinitrile additive achieves both low parasitic reactions and high ionic conductivity, enabling high power output without sacrificing reliability.

Inventive Principle:

Principle #40Composite materials

3Reliability

If electrolytes with entirely different solvent systems are used to reduce parasitic reactions, then parasitic reactions are reduced, but ionic conductivity is significantly lower which precludes high rate capability applications

Engineering Contradiction:

Improveparasitic reaction resistanceVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The dinitrile additive serves as an intermediary substance that mediates between the electrode materials and the base electrolyte solvent. It forms protective interfaces or complexes that reduce direct harmful interactions between the electrolyte and electrodes, thereby suppressing parasitic reactions. Meanwhile, the base electrolyte's high ionic conductivity is preserved because the dinitrile additive does not fundamentally alter the solvent system's transport properties, maintaining fast ion conduction capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 electrolyte system significantly extends the calendar and cycle life of TMCCC-based cells by reducing parasitic reactions, maintaining high ionic conductivity, and tolerating water impurities, thereby improving energy storage efficiency and reducing manufacturing costs.

Implementation Method 1

Performance of this class of electrochemical cell may implicate a rate of parasitic reactions during operation of the cell

Methodology Applied

Scientific EffectParasitic reactions:

Implementation Method 2

energy storage is achieved by ion intercalation in one or more electrodes including the TMCCC material

Methodology Applied

Scientific EffectIon intercalation:

Implementation Method 3

maintaining high ionic conductivity, allowing for fast discharge to extreme depths

Methodology Applied

Scientific EffectIonic conductivity:

Data Source

PatentUS11876182B2Electrochemical cell with TMCCC electrodes in an acetonitrile solvent including a dinitrile additive

Publication Date: 2024.01.16 NATRON (ASSIGNMENT FOR THE BENEFIT OF CREDITORS) LLC

AI summary

A system and method for a liquid electrolyte used in secondary electrochemical cells having at least one electrode including a TMCCC material, the liquid electrolyte enabling an increased lifetime while allowing for fast discharge to extremely high depth of discharge. The addition of dinitriles to liquid electrolytes in electrochemical cells in which energy storage is achieved by ion intercalation in transition metal cyanide coordination compounds (TMCCC) has the advantage of increasing device lifetime by inhibiting common chemical and electrochemical degradation mechanisms.