CoSnC Anode Material for High Energy Density Batteries
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Solution Overview
Problem
Current secondary batteries with alloy materials as anode active materials face challenges in achieving sufficient cycle characteristics and high energy density, particularly due to issues like dendrite growth and internal short circuits, and the surface density ratio optimization is necessary for improved battery characteristics.
Innovation Solution
A battery design incorporating a cathode with a complex oxide containing lithium and cobalt, and an anode with a CoSnC material having a specific carbon content and cobalt-to-tin ratio, along with a controlled surface density ratio between the cathode and anode active material layers, to enhance energy density and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If light metal such as lithium metal is used as anode active material to increase capacity, then energy density is improved, but dendrite precipitation occurs causing cycle life deterioration and internal short circuit
Solution Approach 1:
The patent uses a composite anode active material containing tin (30-70 wt%), nickel (5-30 wt%), and carbon (10-40 wt%). This composite structure combines the high capacity of tin with the stability provided by nickel and carbon, preventing dendrite formation while maintaining high energy density. The carbon component specifically addresses dendrite precipitation by providing a stable matrix that accommodates lithium insertion/extraction without forming dendrites.
2Quantity of substance
If alloy materials are used as anode active material to improve capacity, then energy density is improved, but cycle characteristics are insufficient
Solution Approach 1:
The patent employs a composite material system where tin provides high capacity, nickel enhances structural stability and prevents pulverization during cycling, and carbon provides electrical conductivity and mechanical integrity. This synergistic combination resolves the cycle life issue by distributing mechanical stress and preventing material degradation that occurs with pure alloy materials.
Solution Approach 2:
The patent specifies particular compositional ranges for each element (tin: 30-70 wt%, nickel: 5-30 wt%, carbon: 10-40 wt%) to optimize local properties. The carbon content specifically addresses the cycle life issue by forming a stable protective layer, while tin and nickel ratios are optimized to balance capacity and structural stability during repeated cycling.
3Reliability
If tin-containing anode material is used to improve cycle characteristics, then cycle life is improved, but surface density ratio optimization is required to achieve high energy density
Solution Approach 1:
The patent optimizes the surface density ratio parameter by controlling the compositional ratios of tin, nickel, and carbon within specific ranges. By adjusting these parameters, the anode achieves both improved cycle characteristics (through tin-based alloy structure) and high energy density (through optimized composition and surface density ratio between cathode and anode).
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 superior cycle characteristics by using the CoSnC material with a carbon content of 16.8-24.8 wt% and a cobalt-to-tin ratio of 30-45 wt%, along with a surface density ratio of 2.77-3.90, which improves discharge electric energy and retention ratios.
Implementation Method 1
graphite material utilizing intercalation reaction of lithium ions
Implementation Method 2
carbon material applying insertion and extraction action of lithium ions to and from the fine pores
Data Source
AI summary
A battery capable of improving the energy density and cycle characteristics is provided. A cathode active material layer contains a complex oxide containing Li and Co as a cathode active material. An anode active material layer contains a CoSnC containing material containing Sn, Co, and C as an element, in which the content of C is from 16.8 wt % to 24.8 wt %, and the ratio of Co to the total of Sn and Co is from 30 wt % to 45 wt % as an anode active material. The surface density ratio of the cathode active material layer to the anode active material layer (surface density of the cathode active material layer/surface density of the anode active material layer) is from 2.77 to 3.90.