Elastomer-Encapsulated Anode Particles for Lithium Batteries
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Solution Overview
Problem
Lithium-ion batteries face rapid capacity decay due to mechanical degradation of high-capacity anode active materials like Si and Sn, leading to pulverization, loss of contact with conductive additives and current collectors, and poor cycling stability, with existing protective coatings being brittle and ineffective.
Innovation Solution
Development of an anode active material comprising particulates of high-capacity materials encapsulated in a thin layer of inorganic filler-reinforced elastomer, which provides mechanical strength, toughness, and lithium ion conductivity, preventing excessive expansion and contraction of particles and reducing solid-electrolyte interface formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity anode active materials like Si and Sn are used, then the reversible capacity is improved, but mechanical degradation and pulverization occur during charge-discharge cycles
Solution Approach 1:
The patent applies this principle by encapsulating high-capacity anode active materials (Si, Sn) in a flexible polymer shell that can accommodate volume expansion and contraction during lithium insertion/extraction cycles. The flexible shell prevents mechanical degradation and pulverization while maintaining structural integrity, thus improving cycle life without sacrificing reversible capacity.
Solution Approach 2:
The patent creates a composite material system consisting of high-capacity anode active materials embedded in a polymer matrix. This composite structure combines the high reversible capacity of Si/Sn with the mechanical stability and flexibility of the polymer shell, resolving the contradiction between capacity and cycle life through synergistic material combination.
2Reliability
If protective coatings are applied to prevent mechanical degradation, then cycle life is improved, but the coatings are brittle and ineffective
Solution Approach 1:
The patent replaces traditional brittle protective coatings with a flexible polymer shell that can dynamically respond to volume changes during cycling. This flexible shell maintains coating effectiveness by accommodating expansion/contraction stresses, preventing coating fracture, and thereby improving cycle life through sustained protective function.
Solution Approach 2:
The patent changes the key parameter of the protective layer from rigid/brittle to flexible/elastic. By selecting polymers with appropriate glass transition temperatures and mechanical properties, the shell can adapt its stiffness to match the expansion/contraction behavior of the active material, maintaining protective effectiveness throughout the battery lifecycle.
3Object-affected harmful factors
If SEI layer is formed during initial cycles, then anode surface is protected, but irreversible capacity loss occurs
Solution Approach 1:
The patent introduces a polymer shell as an intermediary layer between the anode active material and the electrolyte. This intermediary shell forms a stable protective interface that prevents direct contact between the electrolyte and active material surface, reducing SEI formation and associated irreversible lithium consumption while still providing necessary surface protection.
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 significantly enhances the cycle life and reversible capacity of lithium-ion batteries by preventing mechanical degradation and maintaining lithium ion conductivity, while minimizing irreversible capacity loss and solid-electrolyte interface formation.
Implementation Method 1
the elastomeric shell has a thickness from 1 nm to 10 μm, a fully recoverable tensile strain from 2% to 500%
Implementation Method 2
inorganic filler-reinforced elastomer having from 0.01% to 50% by weight of an inorganic filler dispersed in an elastomeric matrix material
Implementation Method 3
a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm
Implementation Method 4
provides mechanical strength, toughness, and lithium ion conductivity, preventing excessive expansion and contraction of particles
Implementation Method 5
minimizing irreversible capacity loss and solid-electrolyte interface formation
Data Source
AI summary
A method of producing a powder mass for a lithium battery, comprising: (a) mixing an inorganic filler and an elastomer or its precursor in a liquid medium or solvent to form a suspension; (b) dispersing a plurality of particles of an anode active material in the suspension to form a slurry; and (c) dispensing the slurry and removing the solvent and/or polymerizing or curing the precursor to form the powder mass, wherein at least a particulate is composed of one or a plurality of anode particles being encapsulated by a layer of inorganic filler-reinforced elastomer having a thickness from 1 nm to 10 μm, a fully recoverable tensile strain from 2% to 500%, and a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm and the inorganic filler has a lithium intercalation potential from 1.1 V to 4.5 V versus Li/Li+.