Anode Active Material for Metal Ion Battery Safety and Energy Density
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Solution Overview
Problem
Lithium-ion and sodium-ion secondary batteries face challenges with low energy density and safety issues due to metal lithium and sodium deposition during charging, especially at low temperatures, and existing anode active materials fail to simultaneously increase battery voltage and prevent metal deposition.
Innovation Solution
Development of an anode active material capable of inserting and removing alkali and alkaline-earth metal ions at higher potentials than their equilibrium potentials, preventing metal deposition and enhancing battery safety and voltage, with specific compositions like NaAl3.0(SO4)2·2(OH)5.6·0.30H2O, NaAl1.1Fe1.6(SO4)2(OH)5.1·0.12H2O, NaFe3(SO4)2(OH)6, and KFe3(SO4)2(OH)6, which also support higher charge-discharge capacity and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If graphite-based material is used as anode active material to increase energy density, then battery voltage increases, but metal lithium deposits upon charging especially at low temperature, lowering safety
Solution Approach 1:
The patent changes the operating potential parameter by using an anode active material with a potential of 0.01 to 3.0 V (vs. Li/Li+), which is higher than graphite's potential. This parameter change prevents metal lithium deposition while maintaining acceptable energy density, resolving the safety issue without completely sacrificing energy density.
Solution Approach 2:
The patent employs composite anode active materials that combine multiple components with different potentials. The composite structure includes materials with potentials in the 0.01 to 3.0 V range, creating a multi-phase system that prevents metal deposition while maintaining good electrochemical performance and energy density.
2Reliability
If lithium-titanium complex oxide with spinel structure is used as anode active material to prevent metal lithium deposition, then safety improves, but battery voltage becomes low and energy density decreases
Solution Approach 1:
The patent changes the potential parameter from the conventional 1.5 V (lithium-titanium oxide) to a wider range of 0.01 to 3.0 V, optimizing it to be higher than metal deposition potential but lower than lithium-titanium oxide. This parameter optimization achieves both safety and improved energy density compared to lithium-titanium oxide.
Solution Approach 2:
The patent develops anode active materials that can function in both lithium-ion and sodium-ion batteries, providing universal applicability. The materials with potentials of 0.01 to 3.0 V work effectively for both battery types, preventing metal deposition in both systems while maintaining good electrochemical performance.
3Reliability
If anode active material operates at higher potential to prevent metal deposition, then safety improves, but battery voltage decreases
Solution Approach 1:
The patent optimizes the potential parameter to a specific range (0.01 to 3.0 V vs. Li/Li+) that is higher than metal deposition potential (0 V) but lower than conventional safe materials like lithium-titanium oxide (1.5 V). This optimized parameter range achieves both safety and higher battery voltage, resolving the contradiction between safety and power.
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 anode active materials increase battery voltage and safety by operating within potential ranges that prevent metal deposition, achieving comparable or superior charge-discharge capacity and energy density to graphite and lithium titanium oxide, while ensuring safety and efficiency across various metal-ion batteries.
Implementation Method 1
an anode active material which absorbs and releases lithium ions at a potential of 0 V on the basis of lithium electrode potential
Implementation Method 2
a non-aqueous electrolyte containing lithium ions and sodium ions
Data Source
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Figure 1C
AI summary
A main object of the present invention is to provide an anode active material capable of increasing energy density at the same time increasing battery safety, and a metal ion battery prepared with the anode active material. The present invention is an anode active material comprising an element that belongs to alunite group capable to insert and remove an ion(s) of at least one metal element selected from the group consisting of alkali metal elements and alkaline-earth metal elements, and a metal ion battery having a cathode, an anode, and an electrolyte filled between the cathode and the anode, the electrolyte conducting a metal ion (s), wherein the anode active material is contained in the anode.