Porous Carbon Black Anode Material for Dendrite-Safe Solid Batteries
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Solution Overview
Problem
Solid secondary batteries face issues with lithium dendrite growth and short circuits due to lithium precipitation, which deteriorate battery capacity and can cause short circuits, despite previous attempts to suppress these issues using amorphous carbon as an anode active material.
Innovation Solution
The use of porous carbon black with specific particle size and porosity ranges, combined with elements like silver or zinc that form alloys with lithium, helps in suppressing lithium dendrite growth by adjusting the porosity of the anode active material within a predetermined range, thereby reducing short circuits and improving battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amorphous carbon is used as an anode active material to suppress lithium dendrite growth, then short circuit suppression is improved, but lithium precipitation still occurs at the rear side of the anode active material layer
Solution Approach 1:
The patent applies porous carbon black with specific porosity (0.3-1.5 mL/g) and surface area (5-35 cm²/g × nm) to create a three-dimensional structure that distributes lithium ions more uniformly. The porous structure prevents lithium precipitation by providing additional pathways for ion transport and reducing local concentration gradients, thereby eliminating the harmful effect of lithium dendrite formation at the rear side of the anode layer.
Solution Approach 2:
The patent changes the physical parameters of the carbon material by selecting specific porosity ranges (0.3-1.5 mL/g) and surface area ranges (5-35 cm²/g × nm). These parameter changes optimize the carbon structure to balance lithium ion insertion and prevention of precipitation, resolving the contradiction between short circuit suppression and lithium precipitation control.
2Quantity of substance
If lithium is intercalated in the anode active material layer during charging, then battery capacity is improved, but lithium may precipitate inside or at the rear side of the anode active material layer
Solution Approach 1:
The porous carbon black structure provides increased surface area and interconnected pores that facilitate uniform lithium ion distribution throughout the anode layer. This allows higher battery capacity through efficient lithium intercalation while preventing precipitation by maintaining uniform ion concentration and providing alternative pathways that reduce local saturation.
Solution Approach 2:
The patent uses a composite anode structure combining porous carbon black with specific physical properties (porosity and surface area) to create a material that simultaneously enables high lithium capacity and prevents precipitation. The composite structure integrates the benefits of carbon's electrical conductivity with the pore structure's ion distribution capabilities.
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
This approach effectively suppresses lithium dendrite growth and short circuits, enhancing the stability and capacity of solid secondary batteries by using porous carbon black and specific alloy-forming elements, leading to improved battery characteristics and reduced manufacturing costs.
Implementation Method 1
a value of an average primary particle diameter (cm)×a nitrogen adsorption specific surface area (cm2/g) is greater than or equal to 5 and less than or equal to 35
Implementation Method 2
an element that forms an alloy with lithium by an electrochemical reaction
Data Source
AI summary
Provided is a solid secondary battery capable of more suppressing a short circuit due to generation or growth of dendrites than in the prior art. The anode material comprises amorphous carbon and a first element that forms an alloy with lithium by an electrochemical reaction, wherein the amorphous carbon is carbon black, primary particles of the carbon black are porous, and a value of an average primary particle diameter (cm)×a nitrogen adsorption specific surface area (cm2/g) is greater than or equal to 5 and less than or equal to 35.