Solid-State Lithium Battery Anode With Hollow Carbon and Silver
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Solution Overview
Problem
All-solid lithium secondary batteries face challenges in improving lithium ion storage and discharge efficiency, lifetime, and safety due to the generation of pores between the solid electrolyte and metal layers, which reduces energy density and increases the risk of lithium dendrite formation.
Innovation Solution
Incorporating a negative electrode active material layer with a carbon structure and silver nanoparticles, where the carbon structure includes hollow-type particles with a carbonaceous shell, enhancing lithium ion mobility and storage, and using a reduced amount of silver nanoparticles to improve charge/discharge efficiency and price competitiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a metal layer (lithium metal) is used as negative electrode active material layer to improve energy density, then energy density is improved, but pores are generated between solid electrolyte and metal layer which adversely affects battery operation
Solution Approach 1:
A buffer layer is introduced as an intermediary between the solid electrolyte and the lithium metal layer. This buffer layer prevents direct contact and pore formation between the solid electrolyte and lithium metal, while still allowing lithium ion transport. The buffer layer acts as a mediator that maintains both high energy density (by enabling lithium metal use) and reliable battery operation (by preventing pore generation).
Solution Approach 2:
The negative electrode is designed as a composite structure combining lithium metal layer with buffer layer materials. This composite approach allows the system to benefit from the high capacity of lithium metal while the buffer layer components prevent the harmful pore formation issue, achieving both high energy density and operational reliability.
2Quantity of substance
If lithium metal is used as negative electrode active material layer to improve energy density, then energy density is improved, but lithium dendrites are precipitated on the metal layer surface which degrades lifetime and safety
Solution Approach 1:
The buffer layer serves as a protective intermediary between the lithium metal and the electrolyte, preventing direct interactions that lead to dendrite formation. It mediates the lithium ion deposition process, promoting uniform distribution and preventing the concentration gradients that cause dendritic growth, thereby maintaining safety while preserving high energy density.
Solution Approach 2:
The buffer layer is prepared in advance as a protective cushion between the lithium metal and electrolyte. This pre-established protective layer prevents the harmful dendrite formation process from occurring in the first place, cushioning against the potential damage before it can happen during battery cycling.
3Reliability
If an end plate is disposed to apply high external pressure to prevent pore generation, then pore generation is prevented, but volume of the battery is excessively increased which reduces energy density
Solution Approach 1:
The end plate structure is removed entirely from the battery design. Instead of using an external end plate to apply pressure, the pore prevention function is achieved through the internal buffer layer structure that inherently prevents pore formation without requiring external mechanical pressure, thus eliminating the volume increase problem.
Solution Approach 2:
The mechanical pressure application system (end plate) is replaced with a structural solution (buffer layer). Rather than using mechanical force to prevent pores, the buffer layer's physical structure inherently prevents pore formation through its material properties and configuration, eliminating the need for bulky mechanical pressure components.
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 carbon structure and silver nanoparticles effectively store and mobilize lithium ions, improving initial charge/discharge efficiency and battery life while reducing the need for excessive silver, thus enhancing the energy density and safety of the all-solid lithium secondary battery.
Implementation Method 1
lithium ions are reduced and precipitated by the negative electrode active material layer during charge
Implementation Method 2
the stored lithium may be dissolved in the form of lithium ions during discharge, wherein the lithium ions may move to a positive electrode
Data Source
AI summary
The present disclosure relates to an all-solid lithium secondary battery and a preparation method thereof, wherein the all-solid lithium secondary battery includes a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, wherein the negative electrode active material layer includes a carbon structure and silver nanoparticles, the carbon structure includes at least one hollow-type particle, and the hollow-type particle includes a hollow and a carbonaceous shell surrounding the hollow.