Silicon Anode Binder Using Dopamine-Polymerized Heparin
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Solution Overview
Problem
Lithium secondary batteries face challenges in improving energy density and maintaining electrode stability due to the volume expansion of silicon-based anode materials during charging and discharging, which affects adhesion and lifespan.
Innovation Solution
A binder comprising carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and dopamine-polymerized heparin is used in the anode, which suppresses volume expansion and enhances adhesion, improving output characteristics and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based anode materials are used to increase energy density, then capacity exceeds 4000 mAh/g, but volume expansion occurs during charging and discharging affecting adhesion and lifespan
Solution Approach 1:
The patent uses a composite binder system comprising carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polysaccharide with sulfonate and amine groups. This multi-component composite binder provides both mechanical adhesion and chemical bonding to accommodate silicon's volume expansion while maintaining electrode integrity and adhesion stability throughout charge-discharge cycles.
Solution Approach 2:
The patent modifies the chemical properties of the binder by incorporating polysaccharide with specific functional groups (sulfonate and amine groups) that can chemically interact with silicon. This parameter change in the binder's chemical structure enables it to adapt to silicon's volume changes and maintain stable adhesion during cycling.
2Reliability
If graphite anode is used, then stable adhesion is maintained, but energy density is limited with capacity of 360 mAh/g
Solution Approach 1:
The specialized binder acts as an intermediary between the silicon anode material and the current collector. It mediates the mechanical stress from volume expansion and provides continuous electrical contact, enabling silicon to achieve high capacity while maintaining stable adhesion, thus bridging the performance gap between graphite and silicon.
3Reliability
If binder content is increased to improve adhesion, then electrode stability improves, but energy density decreases
Solution Approach 1:
The patent changes the chemical parameters of the binder by incorporating functional groups (sulfonate and amine groups) that enhance binding efficiency. This allows the binder to provide superior adhesion at lower concentrations, thereby maintaining electrode stability while minimizing the amount of binder needed and preserving energy density.
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 binder effectively improves the output characteristics, life characteristics, and stability of the lithium secondary battery by enhancing adhesion and ion conductivity while maintaining high energy density.
Implementation Method 1
the anode comprises a binder containing carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polysaccharide including a sulfonate functional group and an amine group... dopamine-polymerized heparin... suppresses volume expansion and enhances adhesion
Implementation Method 2
the binder effectively improves the output characteristics, life characteristics, and stability of the lithium secondary battery by enhancing adhesion and ion conductivity
Implementation Method 3
The binder effectively improves the output characteristics, life characteristics, and stability of the lithium secondary battery by enhancing adhesion and ion conductivity
Data Source
AI summary
Disclosed herein is a lithium secondary battery capable of improving an output characteristic, a life characteristic, and stability of electrode adhesion by using a binder containing dopamine-polymerized heparin in an anode containing silicon. In accordance with an aspect of the present disclosure, a lithium secondary battery includes: a cathode; an anode; a separation film disposed between the cathode and the anode; and an electrolyte, wherein the anode comprises a binder containing carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polysaccharide including a sulfonate functional group and an amine group.