Surface-Engineered Carbon Anodes for Low-Irreversible Sodium Storage
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Solution Overview
Problem
Current sodium-ion battery anode materials face challenges with limited reversible specific capacity and high irreversible capacity due to the instability of the solid electrolyte interphase (SEI) layer, leading to reduced first-cycle coulombic efficiency and poor handling characteristics.
Innovation Solution
Development of surface-engineered carbon-containing anode materials with a templated porous carbon core and a carbonized outer surface, featuring a specific surface area and pore structure optimized for enhanced alkali metal ion insertion and extraction, which minimizes irreversible capacity and maximizes reversible specific capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If graphite is used as anode material in lithium-ion batteries, then high gravimetric and volumetric capacity is achieved, but graphite is much less electrochemically active towards sodium and intercalation between graphene layers is severely restricted
Solution Approach 1:
The patent changes the structural parameters of carbon anode materials by creating hard carbon with disordered structures and controlled micropore sizes (0.3-1.5 nm), transforming the material from graphitic to non-graphitic morphology to enable sodium ion intercalation while maintaining high reversible capacity
Solution Approach 2:
The patent employs composite carbon materials combining hard carbon domains with microporous structures, creating a composite anode material that integrates the advantages of both disordered carbon (for sodium insertion) and porous structures (for enhanced electrolyte access and ion transport)
2Reliability
If hard carbon materials with disordered structures are used to overcome insertion issues for sodium ions, then electrochemical activity towards sodium is improved, but first-cycle coulombic efficiency is reduced due to high irreversible capacity
Solution Approach 1:
The patent utilizes microporous hard carbon materials with controlled pore sizes (0.3-1.5 nm) that provide pathways for sodium ion transport while reducing the formation of unstable SEI layers, thereby decreasing irreversible capacity loss and improving first-cycle coulombic efficiency
Solution Approach 2:
The patent optimizes the micropore size parameter to 0.3-1.5 nm and controls the degree of disorder in the carbon structure, transforming the material properties to achieve a balance between sodium ion insertion and minimization of irreversible capacity
3Quantity of substance
If activated carbon material with high specific surface area is used, then alkali metal ion insertion is enhanced, but handling characteristics deteriorate
Solution Approach 1:
The patent employs microporous carbon materials with controlled surface areas and pore sizes that enhance ion insertion while maintaining adequate particle density and mechanical properties for practical handling and electrode fabrication
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 surface-engineered anode materials exhibit improved reversible specific capacity and first-cycle coulombic efficiency, along with reduced irreversible capacity and enhanced handling characteristics, making them suitable for energy storage devices like sodium-ion batteries.
Implementation Method 1
enhanced alkali metal ion insertion and extraction
Implementation Method 2
The surface-engineered anode materials exhibit improved reversible specific capacity
Data Source
AI summary
The invention relates to a carbon-containing anode material which is capable of the insertion and extraction of alkali metal ions. The invention further relates to a process for the preparation of a carbon-containing anode material which is capable of the insertion and extraction of alkali metal ions.