Molten-Salt Cathode Upcycling for Ni-Rich Single-Crystal NMC
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Solution Overview
Problem
Older electric vehicle batteries with nickel-lean cathode materials face degradation issues, leading to reduced ability to hold and deliver electrical energy, and conventional recycling methods are inefficient and unable to produce modern, nickel-rich cathode materials.
Innovation Solution
A one-step molten-salt process is used to upcycle mixed nickel-lean polycrystalline cathodes into nickel-rich single-crystal NMC cathodes by adding nickel and lithium salts as a fluxing agent, eliminating the need for separating constituent elements and producing a single crystal cathode material with enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional recycling methods are used on nickel-lean cathode materials, then the recycling process is simple, but the resulting cathode material has low nickel content and inferior performance compared to modern standards
Solution Approach 1:
The patent changes the chemical composition parameters by adding nickel-containing compounds (such as NiO or NiCO3) and lithium salts to the recycling process. This transforms the nickel-lean cathode material into a nickel-rich composition that meets modern performance standards while maintaining a relatively simple one-step sintering process
Solution Approach 2:
The patent uses lithium salts as an intermediary fluxing agent during the sintering process. This intermediary facilitates the transformation of nickel-lean cathode material into nickel-rich material by enabling controlled chemical reactions and phase transformations without requiring complex separation and recombination steps
2Reliability
If nickel-rich cathode materials are produced through conventional methods, then modern battery chemistry requirements are met, but the recycling process becomes complex and inefficient
Solution Approach 1:
The patent merges multiple operations into a single step: collection of nickel-lean cathode material, addition of nickel sources and lithium salts, sintering, and formation of nickel-rich cathode material. This consolidation eliminates complex separation, purification, and recombination steps required by conventional methods
Solution Approach 2:
The patent achieves nickel-rich composition through direct parameter modification during sintering by controlling the addition of nickel-containing compounds and lithium salts, rather than through complex multi-step processing required by conventional approaches
3Ease of manufacture
If polycrystalline cathode material is used, then the manufacturing process is straightforward, but the specific capacity and cycling stability are limited
Solution Approach 1:
The patent changes the crystal structure parameter by controlling sintering conditions (temperature, time, atmosphere) to promote single-crystal formation from polycrystalline precursor. This structural transformation enhances specific capacity and cycling stability while maintaining manufacturing simplicity
Solution Approach 2:
The patent creates a composite system during sintering where nickel-containing compounds and lithium salts react with the polycrystalline cathode material to form a new single-crystal phase with superior electrochemical properties
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 process significantly increases nickel content, improves specific capacity and cycling stability, and reduces the energy and material requirements compared to traditional recycling methods, resulting in a sustainable and cost-effective production of high-performance cathode materials relevant for modern electric vehicle batteries.
Implementation Method 1
using a molten salt direct recycling process
Implementation Method 2
sintering the combined charge materials for generating a single crystal charge material
Implementation Method 3
The fluxing agent includes an excess of Li for upgrading polycrystalline charge material particles into single crystal charge material particles
Data Source
AI summary
A method for recycling secondary battery charge materials includes a one-step molten-salt process to upcycle mixed Ni-lean polycrystalline NMC cathodes into Ni-rich single-crystal NMC cathodes. The method includes receiving a recycling stream of charge materials from end-of-lifetime batteries, adding additional charge materials based on an upcycled battery chemistry intended for the upgraded, recycled battery, and sintering the combined charge materials for generating a single crystal charge material corresponding to the upcycled battery chemistry using a molten salt direct recycling process.