Li-Ion Cathode Material Precursors With Effluent Recycling
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Solution Overview
Problem
Current methods for producing lithium mixed metal oxides for cathode materials in Li-ion batteries generate significant effluents, requiring costly treatment and energy consumption, and often result in poor product density due to water evaporation and organic/nitrate decomposition during calcination.
Innovation Solution
A two-step process involving a wet chemical precursor fabrication and solid-state lithiation, where raw metals in metallic form are oxidized to form metal hydroxides, with unreacted metals recycled and the liquid portion reused, eliminating the need for effluent treatment and high-temperature water evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional co-precipitation process with mixed metal sulphates and sodium hydroxide is used, then cathode materials can be produced, but significant amounts of Na2SO4-containing effluent are generated requiring costly treatment
Solution Approach 1:
The patent changes the chemical parameters of the precipitation process by using carbonate salts instead of sulphate salts and ammonium hydroxide instead of sodium hydroxide. This parameter change transforms the effluent composition from Na2SO4-containing (harmful) to (NH4)2CO3-containing (benign and reusable), resolving the contradiction between ease of manufacture and harmful effluent generation
Solution Approach 2:
The patent implements a recovery system where the liquid effluent containing ammonium carbonate is not discarded but recovered and reused in the next production cycle. The unreacted carbonate salts are also recovered and reused, eliminating waste discharge and reducing the need for effluent treatment
2Ease of manufacture
If high-temperature calcination is used to produce lithium mixed metal oxide, then cathode materials are formed, but significant energy consumption occurs due to water evaporation and organic/nitrate decomposition
Solution Approach 1:
The patent changes the precursor composition parameters by using inorganic carbonate salts instead of organic salts or nitrates. This eliminates the need for high-temperature decomposition of organic materials, significantly reducing energy consumption during the calcination process while still achieving proper cathode material formation
Solution Approach 2:
The patent performs preliminary carbonation of metal salts to form metal carbonates before the main lithiation process. This preliminary action prepares the precursor in a form that requires less energy for subsequent processing, as carbonate decomposition occurs at lower temperatures compared to organic salt or nitrate decomposition
3Object-affected harmful factors
If conventional effluent treatment processes are applied to remove ammonia and sodium sulphate, then environmental discharge requirements are met, but treatment costs and energy consumption increase significantly
Solution Approach 1:
The patent converts what would traditionally be harmful effluent (ammonium carbonate solution) into a beneficial reusable resource. The ammonium carbonate effluent is recovered and reused as a reagent in subsequent production cycles, transforming a waste stream requiring expensive treatment into a valuable process input, thereby eliminating both treatment costs and energy consumption
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 process minimizes effluent generation, reduces energy consumption, and produces high-quality lithium mixed metal oxides with uniform elemental distribution, achieving efficient and cost-effective production of cathode materials for Li-ion batteries.
Implementation Method 1
raw metals in metallic form are oxidized to form metal hydroxides
Implementation Method 2
the liquid portion reused, eliminating the need for effluent treatment
Implementation Method 3
unreacted metals recycled
Implementation Method 4
solid-state lithiation
Data Source
AI summary
This invention provides an environmental friendly method for the production of high capacity cathode materials for use in Li-ion batteries. Traditional methods for producing lithium mixed metal oxide cathode materials typically generate large amounts of effluent which effluent must be treated prior to discharge. The present process uses mixed metals as raw materials, in a wet chemical reaction with an oxidant, in order to make high-quality metal hydroxide precursors which can be used to prepare high-quality cathode materials after lithiation. As a key feature, in the precursor preparation process, the bulk of the aqueous solution used for the wet chemical reaction can be recycled back to the reactor, so that the total process has little or no effluent generated during production of the cathode precursor material.