High-Nickel NMC Electrodes With Cellulose Hybrid Binder Protection
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Solution Overview
Problem
Current aqueous-based LiNi1-x-yCoxMnyO2 (NMC) electrodes suffer from humidity sensitivity and electrochemical performance issues, hindering their industrialization compared to N-methyl-2-pyrrolidone (NMP)-based electrodes.
Innovation Solution
A method involving a hybrid binder composed of cellulose nanofibers (CNF) and cellulose nanocrystals (CNC) is used to create a water-stable electrode. This binder is combined with active materials and a conductive material in a solvent to form a slurry, which is then dried to produce an electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is used as a solvent for NMC electrode manufacturing, then environmental friendliness and cost-effectiveness are improved, but electrochemical performance and stability deteriorate
Solution Approach 1:
The patent introduces cellulose nanomaterials (CNF and CNC) as intermediary protective coatings on NMC particles. These nanomaterials act as a mediator between the water-based solvent and the humidity-sensitive NMC active material, allowing water to be used as a solvent while preventing harmful interactions with the active material, thus resolving the contradiction between environmental benefits of water and electrochemical stability requirements
Solution Approach 2:
The patent creates a composite electrode structure combining NMC active material particles with cellulose nanomaterials (CNF and CNC) in a hybrid binder system. This composite approach allows the electrode to simultaneously achieve the environmental advantages of water-based processing and the stability of protected NMC surfaces, as the cellulose components provide protection while maintaining electrochemical performance
2Ease of manufacture
If phosphoric acid and metal oxides are added to enable water-based processing, then water-based manufacturing is achieved, but electrochemical performance deteriorates
Solution Approach 1:
The patent replaces harmful chemical additives (phosphoric acid and metal oxides) with sustainable, biodegradable cellulose nanomaterials that serve as temporary protective coatings during manufacturing. These nanomaterials provide the necessary protection for water-based processing without the detrimental electrochemical effects of traditional additives, and they are environmentally benign
Solution Approach 2:
The patent changes the protective coating parameters from inorganic chemicals (phosphoric acid and metal oxides) to organic nanomaterials (cellulose CNF and CNC). This parameter change in the protective layer composition enables water-based processing while maintaining or improving electrochemical performance, as the cellulose materials are electrochemically stable and environmentally friendly
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 use of the CNC-CNF hybrid binder results in electrodes with improved charge capacity, rate performance, and cycling stability, comparable to NMP-based NMC electrodes, while also being environmentally friendly and cost-effective.
Implementation Method 1
the negative surface charge of the cellulose nanomaterials enables them to move forward expeditiously and adsorb onto NMC particles, establishing a protection coverage
Implementation Method 2
the hybrid binder captures water molecules, conducts lithium ions, or captures water molecules and conducts lithium ions
Implementation Method 3
drying the slurry to form an electrode
Data Source
AI summary
Provided herein, in various embodiments, are methods for making a water-stable electrode by combining a mixture of cellulose nanofibers (CNF) and cellulose nanocrystals (CNC). Also described in embodiments herein are water-stables electrode comprising a mixture of CNF and CNC as a hybrid binder. Also described herein are batteries and devices. Also described herein are methods of protecting an electrode in water from delithiation.