Silica-Encapsulated Carbon Composite for High-Capacity Battery Anodes
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Solution Overview
Problem
Conventional lithium battery negative electrode materials, such as carbon-based materials, face limitations in achieving high-power and high-energy density due to their theoretical capacity bottlenecks and poor volume expansion/contraction characteristics, leading to increased internal impedance and reduced battery usability.
Innovation Solution
An energy storage composite particle with a specific structure, comprising a carbon film surrounding a conductive carbon component and energy storage grain, with conductive carbon fibers extending from the inside to the outside, forming a three-dimensional conductive network and providing a buffer space for volume expansion, thereby preventing fracture and enhancing electron transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silica-based negative electrode material is used to achieve high gravimetric capacity, then capacity is improved, but volume expansion increases and material fractures
Solution Approach 1:
The silica-based energy storage grain is nested within a carbon film encapsulation, which is further embedded in a conductive carbon matrix. This nested structure allows the high-capacity silica core to be protected while maintaining its capacity benefits, resolving the contradiction between achieving high gravimetric capacity and maintaining structural integrity during volume expansion.
Solution Approach 2:
A carbon film is formed as a flexible encapsulation layer surrounding the silica-based energy storage grain. This thin film shell accommodates the volume expansion of silica during lithiation while preventing particle fracture, thus maintaining structural integrity while preserving high capacity.
2Stability of the object's composition
If conventional carbon-based negative electrode material is used, then structural stability is maintained, but theoretical capacity is limited
Solution Approach 1:
The invention creates a composite material system combining silica-based energy storage grain (providing high capacity) with carbon film and conductive carbon matrix (providing structural stability). This composite structure integrates the advantages of both materials, achieving high theoretical capacity while maintaining structural stability during charge-discharge cycles.
3Quantity of substance
If silica-based negative electrode material undergoes volume expansion during charge, then capacity is increased, but internal impedance increases and usability decreases
Solution Approach 1:
The conductive carbon matrix is formed with a porous structure that provides buffer space and channels around the silica-based energy storage grain. This porous structure accommodates volume expansion during charging while maintaining conductive pathways, thus preserving both capacity and usability by preventing impedance increase.
Solution Approach 2:
The carbon film and conductive carbon matrix act as intermediary layers between the silica-based energy storage grain and the electrolyte. These intermediaries facilitate ion transport while accommodating volume changes, maintaining both high capacity and good usability by preventing direct contact and impedance increase.
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 energy storage composite particle achieves high gravimetric capacity, high coulomb efficiency, and long cycle life, addressing the limitations of conventional materials by maintaining structural integrity during charge and discharge cycles and improving electron transmission.
Implementation Method 1
the conductive carbon fiber is electrically connected to the conductive carbon component, the energy storage grain, and the carbon film; and the conductive carbon fiber extends from the inside of the space to the outside of the space
Implementation Method 2
as the lithium ion intercalates/deintercalates the silica-based negative electrode material, material expansion and contraction occur on the silica-based negative electrode material
Data Source
AI summary
An energy storage composite particle is provided, which includes a carbon film, a conductive carbon component, an energy storage grain, and a conductive carbon fiber. The carbon film surrounds a space. The conductive carbon component and the energy storage grain are disposed in the space. The conductive carbon fiber is electrically connected to the conductive carbon component, the energy storage grain, and the carbon film, and the conductive carbon fiber extends from the inside of the space to the outside of the space. The energy storage composite particle has a high gravimetric capacity, a high coulomb efficiency, and a long cycle life. Furthermore, a battery negative electrode material and a battery using the energy storage composite particle are also provided.