Silicon Anode Silicate Composition for Coulombic Efficiency and Rate
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Solution Overview
Problem
Existing silicon-based negative electrode active materials in secondary batteries face challenges in achieving high initial coulombic efficiency and kinetic performance, with limitations in conductivity and impedance during lithium ion intercalation/deintercalation.
Innovation Solution
A silicon-based negative electrode active material containing both potassium (K) and iron (Fe) in a silicate form, which enhances conductivity and reduces impedance, improving initial coulombic efficiency and kinetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based materials are used as negative electrode active materials, then high capacity is achieved, but initial coulombic efficiency and kinetic performance are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific elements (Fe, K, Ca, or Sr) into the silicon-based material structure. This modifies the material's properties to improve initial coulombic efficiency while maintaining high capacity, directly resolving the contradiction between quantity of substance and reliability.
Solution Approach 2:
The patent creates composite materials by combining silicon-based materials with alkaline earth metal elements and transition metal elements. This composite structure simultaneously achieves high capacity from silicon and improved initial coulombic efficiency from the added elements, resolving the technical contradiction.
2Quantity of substance
If silicon-based materials are used as negative electrode active materials, then high capacity is achieved, but kinetic performance and rate performance are limited
Solution Approach 1:
The patent modifies kinetic parameters by incorporating Fe, K, Ca, or Sr elements that enhance ionic and electronic conductivity. This changes the material's kinetic properties to improve rate performance while preserving high capacity, resolving the contradiction between quantity of substance and speed.
Solution Approach 2:
By creating composite structures with silicon-based materials and conductive metal elements, the patent achieves both high capacity and improved kinetic performance. The composite material combines the high capacity advantage of silicon with the high conductivity advantage of metal elements.
3Ease of manufacture
If conventional negative electrode materials are used, then manufacturing is simple, but energy density is insufficient
Solution Approach 1:
The patent adjusts compositional parameters by adding specific elements at controlled concentrations to silicon-based materials. This maintains relatively simple manufacturing processes while significantly improving energy density, resolving the contradiction between ease of manufacture and quantity of substance.
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 combination of K and Fe in the silicate structure improves the initial coulombic efficiency and kinetic performance of the silicon-based negative electrode, enabling high energy density and rate performance in secondary batteries.
Implementation Method 1
The presence of the element Fe improves conductivity of active ions and electrons during intercalation/deintercalation of active ions (lithium ions) of the negative electrode active material
Implementation Method 2
potassium silicate generated by reaction of the element K and a silicon-oxygen material helps to improve capacity utilization of the negative electrode active material
Data Source
AI summary
A silicon-based negative electrode active material, a method for preparing the silicon-based negative electrode active material, and a secondary battery including a negative electrode that includes the silicon-based negative electrode active material. The silicon-based negative electrode active material includes a silicate. The silicate contains an alkaline earth metal element, and the silicon-based negative electrode active material contains both the element K and the element Fe.