Potassium Ion Battery Negative Electrode Binder
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Solution Overview
Problem
There is a lack of reported structures for reproducible potassium-ion secondary batteries, and no electrochemical reversible intercalation-release reaction has been achieved for potassium ions in graphite electrodes, limiting the development of potassium-ion batteries with high cycle durability and long life.
Innovation Solution
A negative electrode for potassium-ion batteries comprising a carbon material capable of occluding and releasing potassium ions, combined with a binder including polycarboxylic acid and/or its salt, such as polyacrylic acid or its alkali metal salts, which enhances cycle durability and reversible capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If graphite is used as a negative electrode material for potassium-ion batteries, then fast diffusion rate of potassium ions is achieved, but electrochemical reversible intercalation-release reaction has not been realized
Solution Approach 1:
The patent changes the chemical parameters of the binder material from conventional PVdF to polycarboxylic acid and its salts, which have different chemical properties including carboxyl groups that can interact with potassium ions. This parameter change enables the binder to participate in the electrochemical reaction and facilitate reversible intercalation-release of potassium ions in graphite electrodes.
Solution Approach 2:
The patent creates a composite electrode structure combining graphite particles with polycarboxylic acid binder, where the binder forms a matrix that supports the graphite and provides chemical interaction sites for potassium ions. This composite approach combines the fast diffusion properties of graphite with the chemical reactivity of polycarboxylic acid to achieve both high speed and reliability.
2Stability of the object's composition
If conventional binders like PVdF are used in potassium-ion battery electrodes, then electrode structure is maintained, but cycle durability is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the binder from fluorinated polymers (PVdF) to carboxylic acid polymers, which have different functional groups capable of stronger chemical interactions with potassium ions and electrode materials. This compositional change enhances the binder's ability to maintain electrode structure during cycling, thereby improving cycle durability.
Solution Approach 2:
The polycarboxylic acid binder acts as an intermediary substance that mediates between the potassium ions and the graphite electrode structure. The carboxyl groups in the binder form intermediate complexes with potassium ions during intercalation and release processes, stabilizing the electrode structure and preventing degradation over multiple cycles.
3Quantity of substance
If potassium-ion batteries are developed as alternatives to lithium-ion batteries, then resource availability and cost are improved, but reproducible battery structures are lacking
Solution Approach 1:
The patent copies the successful lithium-ion battery electrode structure using graphite as negative electrode material, but adapts it for potassium-ion batteries by changing the binder material. This copying approach allows replication of the proven lithium-ion battery architecture while substituting lithium with potassium, thereby achieving resource availability benefits without sacrificing manufacturability.
Solution Approach 2:
The polycarboxylic acid binder serves multiple functions simultaneously: it maintains electrode structure, facilitates potassium ion transport, enables reversible intercalation-release reactions, and improves cycle durability. This multi-functionality simplifies the overall battery design and enhances ease of manufacture by using a single material to address multiple requirements.
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 provides potassium-ion batteries with superior cycle durability, long life, and high reversible capacity, enabling their use in both secondary batteries and capacitors.
Implementation Method 1
a carbon material capable of occluding and releasing potassium ions
Implementation Method 2
a binder including polycarboxylic acid and/or a salt thereof
Data Source
AI summary
Provided are: a potassium ion secondary battery which is not susceptible to deterioration of charge/discharge capacity even if charging and discharging are repeated, and which has a long service life as a secondary battery; a potassium ion capacitor; a negative electrode for the potassium ion secondary battery; and a negative electrode for the potassium ion capacitor. A negative electrode for potassium ion secondary batteries and a negative electrode for potassium ion capacitors, each of which contains a carbon material that is capable of absorbing and desorbing potassium and a binder that contains a polycarboxylic acid and/or a salt thereof. A potassium ion secondary battery which is provided with the negative electrode or the capacitor. A binder for negative electrodes of potassium ion secondary batteries or negative electrodes of potassium ion capacitors, which contains a polycarboxylic acid and/or a salt thereof.