Metal Composite Anode Materials for Lithium Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high energy density and long durability due to limitations in anode materials, particularly with silicon and silicon oxides which crack from volume changes during charging and discharging, leading to reduced capacity and cycle-life.
Innovation Solution
The development of metal composites comprising a metal oxide and a metal carbon alloy, such as Sn-Co-C alloys combined with metal oxides like SiO2 or SnO2, which buffer volume expansion and minimize conductivity issues from Li2O formation, enhancing cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon or silicon oxide is used as anode material to increase capacity, then the battery capacity increases, but the anode cracks due to volume expansion during charging and discharging, reducing cycle-life
Solution Approach 1:
The patent applies composite materials by combining silicon oxide particles with a metal matrix (such as aluminum, copper, or nickel) to create a composite anode material. The metal matrix serves as a buffer that accommodates the volume expansion of silicon oxide during lithium insertion, preventing crack formation while maintaining high capacity. This composite structure allows the silicon oxide to contribute its high theoretical capacity (4200 mAh/g) without suffering from the volume expansion-induced degradation that plagues pure silicon anodes.
2Quantity of substance
If non-carbon based anodes such as metal alloys are used to achieve higher capacity, then the battery capacity increases, but the volume expansion during lithium insertion and de-insertion causes structural degradation
Solution Approach 1:
The patent employs the metal matrix as an intermediary material that mediates between the silicon oxide particles and the lithium ions. The metal matrix provides a stable structural framework that undergoes minimal volume change during lithium insertion and de-insertion, while still allowing the silicon oxide to expand and contract. This intermediary structure prevents direct structural degradation of the active material and maintains electrical conductivity throughout the cycling process.
3Quantity of substance
If more silicon is added to increase capacity, then the battery capacity increases, but the large volume expansion and poor cycleability worsen
Solution Approach 1:
The patent utilizes parameter changes by controlling the particle size, morphology, and distribution of silicon oxide within the metal matrix. By optimizing these parameters, the patent achieves a balance between capacity and volume expansion management. Additionally, the metal matrix composition and microstructure are adjusted to provide appropriate mechanical properties that accommodate silicon oxide expansion without compromising structural integrity or electrical conductivity.
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
These composite materials demonstrate improved initial charge-discharge efficiency and extended cycle-life, maintaining capacity over numerous cycles without significant fade, outperforming standalone silicon or silicon oxide anodes.
Implementation Method 1
the poor conductivity effect of Li2O forming during the conversion reaction of the metal oxide with lithium
Implementation Method 2
the metal is electrochemically alloyed with lithium, and the resulting alloy is then susceptible to reversible lithium insertion and de-insertion in a battery environment
Data Source
AI summary
An electrochemical device includes a composite material of general Formula (1-x)J-(x)Q wherein: J is a metal carbon alloy of formula SnzSiz′MetwMet′w′Ct; Q is a metal oxide of formula AγMαM′α′Oβ; and wherein: A is Li, Na, or K; M and M′ are individually Ge, Mo, Al, Ga, As, Sb, Te, Ti, Ta, Zr, Ca, Mg, Sr, Ba, Li, Na, K, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Rt, Ru or Cd; Met and Met′ are individually Ge, Mo, Al, Ga, As, Sb, Te, Ti, Ta, Zr, Ca, Mg, Sr, Ba, Li, Na, K, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Rt, Ru or Cd; 0<x<1; γ is 0, 1, or 2; 0<α≦1; 0≦α′≦1; β is 0.5, 1, 2, or 3; 0<t≦5; 1≦w≦5; 0<w′≦5; 1≦z≦5; and 0<z′≦5.