Lithium Silicate Electrode Additive for Capacity Loss Compensation

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Solution Overview

Problem

Conventional lithium-ion batteries experience irreversible capacity loss due to lithium ion consumption during the first cycle, leading to decreased specific energy and power, with losses ranging from 5% to 30% due to the formation of a solid electrolyte interphase (SEI) layer and ongoing lithium loss.

Innovation Solution

Incorporating a lithiation additive, such as lithium silicate (Li2HrSiOz) into the electrode, where 0≤y≤3.75 and 0≤z≤2, to create a lithium source that compensates for cycle-induced lithium loss, thereby maintaining the battery's capacity by forming a lithiation layer adjacent to the current collector and an electroactive layer on its surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lithium-ion batteries are used without pre-lithiation, then the battery structure is simple and manufacturing is easier, but irreversible capacity loss occurs due to lithium ion consumption during the first cycle

Engineering Contradiction:

Improvebattery capacity retentionVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by incorporating a lithiation additive into the electrode structure before the battery undergoes its first charge-discharge cycle. This pre-lithiation process occurs during electrode manufacturing, where the additive is mixed with the active material and binder. During the first cycle, this pre-incorporated lithium source compensates for the lithium consumed in forming the SEI layer, thereby preventing irreversible capacity loss and improving battery capacity retention without requiring complex post-manufacturing modifications

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a lithiation additive is incorporated into the electrode to compensate for lithium loss, then capacity retention improves, but the electrode manufacturing process becomes more complex

Engineering Contradiction:

Improvecapacity loss reductionVSAvoidelectrode fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the lithiation additive with the existing electrode components (active material and binder) into a single homogeneous mixture during the standard electrode fabrication process. The additive is combined with the active material particles and binder in a slurry or dry mix, then processed through conventional methods such as coating, drying, and calendaring. This integration allows the pre-lithiation function to be incorporated without requiring separate manufacturing steps or specialized equipment, thereby maintaining ease of manufacture while achieving capacity loss reduction

Inventive Principle:

Principle #5Merging (Combining)

3Power

If lithiation additive is added to create a lithium reservoir, then specific energy and power are enhanced, but the quantity of substances in the electrode increases

Engineering Contradiction:

Improvespecific power and energyVSAvoidelectrode material composition

Core Design Contradiction:

PowerVSQuantity of substance

Solution Approach 1:

The patent applies local quality by incorporating the lithiation additive in specific locations within the electrode structure rather than uniformly distributing it throughout the entire battery system. The additive is localized within the electrode material itself, concentrated in regions where it can effectively serve as a lithium reservoir during cycling. This localized approach provides the necessary lithium compensation to enhance specific power and energy while minimizing the overall quantity of additional substances required, as the additive is confined to the electrode rather than being distributed system-wide

Inventive Principle:

Principle #3Local quality

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 method reduces capacity loss to less than or equal to 5% of the initial capacity, enhancing the battery's specific power and energy by acting as a lithium reservoir and minimizing undesirable side reactions.

Implementation Method 1

adding a lithiation additive to the at least one electrode to create a lithium source that compensates for cycle-induced lithium loss

Methodology Applied

Scientific EffectDe-lithiation:

Implementation Method 2

forming a lithiation layer adjacent to the current collector and an electroactive layer on its surface

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS11527745B2Methods of pre-lithiating electrodes

Publication Date: 2022.12.13 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

The present disclosure provides methods of compensation for capacity loss resulting from cycle-induced lithium consumption in an electrochemical cell including at least one electrode. Such methods may include adding a lithiation additive to the at least one electrode so as to create a lithium source. The lithium source compensates for cycle-induced lithiation loss such that the electrochemical cell having the lithiation additive experiences total capacity losses of less than or equal to about 5% of an initial capacity prior to cycling of lithium. The lithiation additive includes a lithium silicate represented by the formula LiuHr, where Hr=Liy-uSiOz and where 0≤y≤3.75 and 0≤z≤2 and u is a useable portion of y, 0≤u≤y. The lithium source may includez4⁢L⁢ i4⁢Si⁢ O4and LimSi, where 0≤m≤4.4.