Lithium Secondary Battery Buffering Layer for Dendrite Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium secondary batteries face challenges with insufficient energy density and cycle characteristics, as well as significant volumetric changes during charging and discharging due to lithium metal precipitation, leading to potential short circuits and capacity reduction.
Innovation Solution
A lithium secondary battery design featuring a negative electrode without active material, a fibrous or porous buffering function layer with ionic and electronic conductivity between the electrodes, which allows lithium metal to precipitate and dissolve, controlling the reaction rate and suppressing dendrite growth, thereby enhancing energy density and cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is precipitated on the negative electrode surface to achieve high energy density, then energy density is improved, but dendrite formation occurs leading to poor cycle characteristics
Solution Approach 1:
A buffering function layer is introduced as an intermediary between the negative electrode and separator. This layer mediates the lithium metal precipitation process, providing a controlled interface that prevents direct dendrite growth while maintaining high lithium content. The buffering layer acts as a buffer zone that accommodates volume changes and suppresses harmful dendrite formation.
Solution Approach 2:
The buffering function layer is designed with a porous structure that allows lithium ions to penetrate while providing nucleation sites for controlled lithium metal deposition. The porous structure prevents dense dendrite formation by distributing lithium precipitation across multiple pathways, thereby improving cycle characteristics while maintaining energy density.
2Reliability
If physical pressure is applied to suppress dendrite growth, then cycle characteristic is improved, but battery weight and volume increase reducing energy density
Solution Approach 1:
The mechanical pressure system is replaced with a chemical/structural solution. Instead of applying external physical pressure through mechanical mechanisms, the buffering function layer provides intrinsic structural support and controlled lithium deposition pathways that suppress dendrites without requiring additional mechanical components, thereby avoiding weight and volume penalties.
Solution Approach 2:
The buffering function layer serves as an intermediary that eliminates the need for mechanical pressure systems. It provides a controlled interface that naturally suppresses dendrite growth through its material properties and structure, replacing the need for heavy mechanical compression mechanisms.
3Quantity of substance
If lithium metal is precipitated during charging, then high capacity is achieved, but significant volumetric change occurs during charge/discharge
Solution Approach 1:
The porous buffering function layer accommodates the volumetric changes associated with lithium metal precipitation and dissolution. The porous structure expands and contracts to absorb volume changes, preventing significant cell swelling or shrinking while maintaining high lithium capacity.
Solution Approach 2:
The buffering function layer acts as a nested structure that contains the lithium metal precipitation within its porous matrix. This nested configuration allows the lithium to be housed within the buffering layer's structure, minimizing external volume changes of the cell during charge/discharge cycles.
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 battery achieves high energy density and improved cycle characteristics while minimizing volumetric changes during charge/discharge, ensuring enhanced safety and performance.
Implementation Method 1
the buffering function layer having ionic conductivity and electronic conductivity
Implementation Method 2
the buffering function layer having ionic conductivity and electronic conductivity
Implementation Method 3
a conventional lithium-metal secondary battery which precipitates a lithium metal on the surface of a negative electrode
Implementation Method 4
perform charge/discharge by delivering or receiving lithium ions between a positive-electrode active material and a negative-electrode active material
Data Source
AI summary
The purpose of the present invention is to provide a lithium secondary battery which has a high energy density and an excellent cycle characteristic and is suppressed from a volumetric change of a cell due to charge/discharge. The present invention relates to a lithium secondary battery having a positive electrode, a negative electrode not having a negative-electrode active material, a separator or a solid electrolyte placed between the positive electrode and the negative electrode, and a fibrous or porous buffering function layer formed on the surface of the separator or the solid electrolyte facing the negative electrode, the buffering function layer having ionic conductivity and electronic conductivity.