Coated Lithium-Ion Sieve for Manganese Dissolution Control
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Solution Overview
Problem
Spinel-type lithium manganese oxide (LMO) materials suffer from high manganese dissolution and pollution in desorption solutions, limiting their industrial application due to reduced adsorption capacity and stability.
Innovation Solution
A coated lithium-ion sieve with a Li1.6Mn1.6O4 inner shell and a coating layer of Li2O, Li2MnO3, or MnO2, with a diameter of 45-55 nm and a coating thickness of 2-4 nm, prepared through calcination, mixing, and acid treatment to enhance stability and adsorption capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If spinel-type lithium manganese oxide (LMO) is used as adsorbent, then adsorption capacity is improved, but manganese dissolution increases and chemical stability deteriorates
Solution Approach 1:
The patent applies composite materials by combining Li1.6Mn1.6O4 core with a protective coating layer of Li2MnO3 or MnO2. This composite structure maintains the high adsorption capacity of the LMO core while the coating layer provides chemical stability and prevents manganese dissolution. The coating layer acts as a barrier between the LMO and the aqueous environment, resolving the contradiction between adsorption performance and chemical stability.
Solution Approach 2:
The patent applies local quality by creating a coated structure where the core (Li1.6Mn1.6O4) and coating layer (Li2MnO3 or MnO2) have different local properties. The core provides high adsorption capacity while the coating layer provides chemical stability and manganese protection. This local differentiation allows each region to optimize its function, resolving the contradiction between adsorption capacity and chemical stability.
2Reliability
If doping modification is applied to reduce manganese dissolution, then chemical stability is improved, but adsorption capacity decreases
Solution Approach 1:
The patent applies segmentation by separating the functional requirements into two distinct parts: the Li1.6Mn1.6O4 core that provides adsorption capacity and the Li2MnO3/MnO2 coating layer that provides chemical stability. This segmentation avoids the need to compromise adsorption capacity through doping, as the coating layer provides stability without replacing active lithium sites in the core structure.
Solution Approach 2:
The patent uses the coating layer as an intermediary between the LMO core and the aqueous environment. This intermediary layer protects the core from chemical degradation and manganese dissolution while allowing lithium ion transport. The coating acts as a mediator that provides chemical stability without directly participating in adsorption, thus maintaining the core's adsorption capacity.
3Loss of substance
If coating layer is applied to prevent manganese dissolution, then manganese retention is improved, but adsorption capacity may be reduced
Solution Approach 1:
The patent applies a thin film coating layer (Li2MnO3 or MnO2) that is thin enough to allow lithium ion diffusion while providing effective protection against manganese dissolution. The thin film structure maintains porosity and ion transport pathways, ensuring that adsorption capacity is not significantly reduced while achieving improved manganese retention.
Solution Approach 2:
The coating layer is designed with porous structure that allows lithium ion transport while providing protective function. The porous structure maintains ion diffusion pathways and prevents the coating from blocking access to the core's adsorption sites, thus balancing manganese retention with adsorption capacity maintenance.
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 coated lithium-ion sieve exhibits improved manganese retention, higher adsorption capacity, and enhanced cycle stability, allowing for multiple reuse cycles with maintained performance.
Implementation Method 1
a coated lithium-ion sieve, comprising an inner shell and a coating layer, the coating layer uniformly covers the outside of the inner shell
Implementation Method 2
spinel-type lithium manganese oxide (LMO) has caused considerable research hotspots due to its higher adsorption capacity and Li+ selectivity
Implementation Method 3
performing an acid treatment to the oxide-coated Li1.6Mn1.6O4 lithium-ion adsorbent to form an acidified product
Data Source
AI summary
The present invention disclosures a preparation method for a coated lithium ion sieve, the method comprises: S01: calcining manganese salt in an air atmosphere for 2 h˜10 h to form Mn2O3; S02: mixing Mn2O3 with lithium salt and grinding, reacting in a high-pressure reaction kettle at 100° C.˜200° C. for 36 h˜72 h to form a product of LiMnO2; wherein, the molar ratio of Mn2O3 and Li/Mn in the lithium salt is 1:1˜10:1; S03: adding LiMnO2 to a metal coating reagent and ultrasonic mixing for 2 h˜10 h, drying for 6 h˜24 h, and then calcining at 400° C.˜600° C. for 2 h˜10 h to form an oxide-coated Li1.6Mn1.6O4 lithium ion adsorbent; Wherein, the molar ratio of the metal coating reagent to LiMnO2 is 0.01:1˜0.08:1; S04: performing an acid treatment to the oxide-coated Li1.6Mn1.6O4 lithium-ion adsorbent to form an acidified product, washing the acidified product and drying to form the coated lithium-ion sieve. The cell structure of the coated lithium-ion sieve of the present invention is more stabler and can be reused for many cycles, which solves a problem that traditional HMn2O4 lithium-ion sieve is easy to dissolve.