Nanometal Core-Shell Electrode for Lithium Battery
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Solution Overview
Problem
Lithium batteries using non-carbonaceous materials like silicon, tin, and nickel face issues with volume expansion and lithium precipitation during charging and discharging, leading to reduced cycle lifetime and capacity.
Innovation Solution
A negative electrode active material comprising nanometal particles and super-conductive nanoparticles with specific structural and dimensional characteristics, including polycyclic nano-sheets and pitch-coating, is developed to enhance capacity and lifetime characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-carbonaceous materials like silicon, tin, and nickel are used as negative electrode active materials, then capacity is improved, but cycle lifetime deteriorates due to volume expansion and shrinkage during charging and discharging
Solution Approach 1:
The patent applies the nesting principle by placing nanometal particles inside hollow carbon spheres, creating a core-shell structure where the carbon sphere acts as a protective container for the active nanometal material. This nested configuration allows the high-capacity nanometal particles to be shielded from degradation while maintaining their electrochemical activity, thus resolving the contradiction between high capacity and long cycle lifetime
Solution Approach 2:
The hollow carbon sphere shell provides a flexible yet structurally stable container that can accommodate volume changes of the enclosed nanometal particles during lithium insertion and extraction. The carbon shell acts as a buffer that prevents catastrophic structural failure, enabling the electrode to maintain integrity over many charge-discharge cycles while preserving the high capacity of the nanometal core
2Productivity
If nanometal particles are used to increase capacity, then charging and discharging efficiency is improved, but damage from volume expansion occurs
Solution Approach 1:
The hollow carbon sphere shell provides a flexible yet structurally stable container that can accommodate volume changes of the enclosed nanometal particles during lithium insertion and extraction. The carbon shell acts as a buffer that prevents catastrophic structural failure, enabling the electrode to maintain integrity over many charge-discharge cycles while preserving the high capacity of the nanometal core
Solution Approach 2:
The hollow carbon sphere structure provides pre-established protective cushioning for the nanometal particles before volume expansion damage can occur. The empty space within the hollow sphere and the carbon shell itself act as a buffer zone that absorbs expansion stress, preventing direct contact and mechanical damage between expanding particles and the electrode matrix
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 effectively reduces damage from volume expansion and improves the capacity and lifetime of lithium batteries by using nanometal particles and super-conductive nanoparticles, resulting in enhanced charging and discharging efficiency.
Implementation Method 1
super-conductive nanoparticles
Implementation Method 2
Carbonaceous materials in various forms, such as artificial graphite, natural graphite and hard carbon, which allow intercalation and deintercalation of lithium ions
Data Source
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AI summary
A negative electrode active material including nanometal particles and super-conductive nanoparticles and a lithium battery including the same. Each of the super-conductive nanoparticles comprises a number of polycyclic nano-sheets including interconnected carbon atoms. The nanoparticle may comprise a material selected from the group consisting of silicon, tin, nickel and mixtures thereof.