Pre-formed SEI Anode Material for Lithium-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face challenges with anode materials that suffer from mechanical degradation, leading to shortened cycle life, high irreversible capacity, and poor cycling stability due to pulverization of alloy particles during lithium ion insertion and extraction, and the formation of a solid electrolyte interface (SEI) that results in lithium loss.
Innovation Solution
Development of an anode active material with a pre-formed solid-electrolyte interphase (SEI) and a protecting shell that encapsulates the anode active material particles, allowing for controlled lithiation and delithiation processes to maximize lithium storage capacity and minimize irreversible capacity loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If alloy particles are used as anode active material to increase lithium storage capacity, then the specific capacity is improved, but the particles undergo pulverization during lithium ion insertion and extraction, resulting in shortened cycle life
Solution Approach 1:
A protecting shell is formed around the anode active material particles to encapsulate them. This shell accommodates the volume expansion and contraction during lithiation and delithiation, preventing pulverization and maintaining particle integrity over multiple charge-discharge cycles, thus improving cycle life while preserving high lithium storage capacity.
Solution Approach 2:
The anode is constructed as a composite system consisting of the core anode active material particles (providing high capacity) surrounded by a protecting shell (providing mechanical stability). This composite structure combines the advantages of both components to achieve high capacity and long cycle life simultaneously.
2Ease of manufacture
If conventional anode materials are used, then the battery can operate, but mechanical degradation occurs leading to loss of particle-to-particle contacts and significantly shortened charge-discharge cycle life
Solution Approach 1:
The protecting shell acts as a flexible encapsulation that maintains particle integrity and prevents loss of electrical contacts during mechanical degradation, ensuring long-term operational durability without complicating the manufacturing process.
3Object-affected harmful factors
If lithium-ion batteries replace pure lithium metal with carbonaceous materials to improve safety, then safety is improved, but irreversible capacity loss occurs and energy density decreases
Solution Approach 1:
The invention changes the material parameter from conventional carbonaceous anodes to high-capacity alloy particles with a protecting shell. This parameter change enables the anode to achieve both the safety of non-metallic materials and the high reversible capacity characteristic of lithium alloys, reducing irreversible capacity loss.
4Quantity of substance
If high-capacity alloy materials like Si, Sn, or Ge are used to maximize lithium storage, then the theoretical specific capacity is improved, but the anode material undergoes severe expansion and contraction, causing fragmentation
Solution Approach 1:
The protecting shell provides a compliant encapsulation that accommodates the severe expansion and contraction of high-capacity alloy materials during lithiation and delithiation. This prevents fragmentation and maintains structural integrity, enabling the use of high-capacity materials like Si, Sn, and Ge without suffering from their inherent mechanical instability.
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 enhances the cycle life and stability of lithium-ion batteries by maintaining lithium storage capacity and reducing irreversible capacity loss, resulting in improved performance and efficiency.
Implementation Method 1
carbonaceous materials as the negative electrode (anode). The carbonaceous material may comprise primarily graphite that is intercalated with lithium and the resulting graphite intercalation compound may be expressed as LixC6
Implementation Method 2
the formation of a solid electrolyte interface (SEI) that results in lithium loss
Data Source
AI summary
Provided is anode active material for use in a lithium ion battery, wherein the anode active material is capable of reversibly storing lithium ions therein up to a maximum lithium storage capacity Cmax during a charge or discharge of the battery and the anode active material comprises an amount of solid-electrolyte interphase (SEI) on a surface or in an internal structure of the anode active material wherein the SEI is pre-formed prior to incorporating the anode active material in an anode electrode of the battery. Also provided is a method of producing the pre-formed SEI substances in the anode material; e.g. through repeated lithiation/delithiation procedures.