Composite Anode Active Material for Lithium Battery Thermal Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium batteries face challenges in achieving high thermal stability, high-rate characteristics, and long lifetime due to limitations in anode active materials, such as carbonaceous materials with low battery capacity and metals that degrade easily, leading to short lifetimes and thermal runaway issues.

Innovation Solution

A composite anode active material is developed, comprising a first crystalline carbonaceous material with carbon nanosheets, a non-carbonaceous material capable of intercalating and deintercalating lithium, and a second carbonaceous material that binds them, with pores of at least 50 nm, prepared through a method involving mixing, spray-drying, and sintering to enhance conductivity and volume change tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbonaceous materials are used as anode active material, then thermal stability and structural stability are improved, but battery capacity is reduced

Engineering Contradiction:

Improvethermal stabilityVSAvoidbattery capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent creates a composite anode material consisting of a carbonaceous matrix (graphite or amorphous carbon) containing metal particles (Si, Sn, Al, or their alloys). The carbonaceous component provides thermal stability and structural integrity, while the metal particles contribute high capacity through alloying with lithium. This composite structure resolves the contradiction by combining materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The metal particles are distributed locally within the carbonaceous matrix, creating regions of high capacity (metal particles) embedded in a stable background (carbon matrix). This local distribution allows the battery to achieve high overall capacity while maintaining thermal stability throughout the structure.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If metals alloyable with lithium are used as anode active material, then battery capacity is improved, but lifetime and stability are reduced

Engineering Contradiction:

Improvebattery capacityVSAvoidlifetime

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The carbonaceous matrix acts as a flexible container that accommodates the volume expansion and contraction of metal particles during lithium alloying and de-alloying cycles. This protective carbon shell prevents particle degradation, aggregation, and electrical shorting, thereby extending battery lifetime while maintaining high capacity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The carbonaceous matrix is designed to preemptively absorb and cushion the mechanical stress generated by volume changes during cycling. This prior cushioning prevents particle crushing and aggregation before they can occur, maintaining electrode integrity over many cycles.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If porous structure is used in anode active material, then volume change tolerance is improved, but battery capacity is reduced

Engineering Contradiction:

Improvevolume change toleranceVSAvoidbattery capacity

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent utilizes the porous structure of the carbonaceous matrix to accommodate metal particles and facilitate volume changes during lithium alloying. The pores provide space for expansion without compromising overall electrode density, thereby maintaining high capacity while tolerating volume changes.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

Metal particles are nested within the porous carbonaceous matrix structure. This nesting arrangement allows the metal particles to expand and contract within the confined porous spaces of the carbon matrix, accommodating volume changes while maintaining high electrode density and capacity.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 composite anode active material improves initial efficiency, discharge capacity, and lifetime of lithium batteries by providing improved conductivity and tolerating volume changes during charging and discharging, resulting in enhanced high-rate characteristics and thermal stability.

Implementation Method 1

a non-carbonaceous material capable of intercalating and deintercalating lithium

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

spray-drying the mixture slurry to obtain a dried product

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

sintering the dried product to obtain the composite anode active material

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS9105904B2Composite anode active material, anode and lithium battery including the same, and method of preparing composite anode active material

Publication Date: 2015.08.11 SAMSUNG SDI CO LTD

AI summary

In an aspect, a composite anode active material including particles, wherein the particles include: a first carbonaceous material that is substantially crystalline and includes at least one carbon nano-sheet; a non-carbonaceous material capable of intercalating and deintercalating lithium; and a second carbonaceous material that binds the first carbonaceous material and the non-carbonaceous material, wherein the particles have pores having a size of 50 nm or more is disclosed.