Core-Shell Cathode Precursor With Iron Coating for Higher Capacity
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Solution Overview
Problem
Existing lithium-ion secondary batteries face challenges in achieving high discharge capacity due to the use of cobalt-based materials, which are expensive and pose resource risks, and there is a need for cobalt-free alternatives that can enhance energy efficiency.
Innovation Solution
A cobalt-free positive electrode active material precursor with a core-shell structure, where the core contains nickel and aluminum, and the shell is coated with an iron compound, ensuring a uniform distribution of iron and suppressing aluminum richness on the surface, resulting in increased discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt-based materials are used for positive electrode active material precursor, then battery capacity can be maintained, but cost increases and resource risk arises
Solution Approach 1:
The patent replaces expensive cobalt-based materials with cheaper cobalt-free materials (nickel, iron, aluminum-based hydroxides). Although cobalt-free materials individually have lower capacity, the core-shell structure design enables them to achieve comparable overall battery capacity while reducing material cost and resource risk
Solution Approach 2:
The patent creates a composite positive electrode active material precursor combining nickel hydroxide (core) with iron and aluminum hydroxide (shell). This composite structure leverages the high capacity of nickel while using iron and aluminum to suppress surface aluminum richness and improve overall battery performance, achieving both cost reduction and capacity maintenance
2Productivity
If cobalt-free materials with uniform metal distribution are used, then discharge capacity increases, but manufacturing complexity increases due to core-shell structure requirements
Solution Approach 1:
The patent applies preliminary action by forming the core-shell structure in advance during the coprecipitation process. The iron and aluminum hydroxide shell is deposited on the nickel hydroxide core before battery assembly, ensuring uniform metal distribution and suppressing surface aluminum richness from the outset, which leads to enhanced discharge capacity
Solution Approach 2:
The patent applies local quality by creating distinct regions within the particle: the core contains nickel hydroxide for high capacity, while the shell contains iron and aluminum hydroxide to suppress surface aluminum richness. This spatial differentiation of material properties optimizes both capacity and performance without requiring complex post-processing
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 precursor leads to a lithium-ion secondary battery with enhanced discharge capacity, reducing the number of batteries required and contributing to cost reduction by optimizing the core-shell structure and distribution of metal elements.
Implementation Method 1
a positive electrode active material precursor in which nickel, iron, and aluminum are converted into a hydroxide by a coprecipitation process
Data Source
AI summary
A positive electrode active material precursor for a lithium-ion secondary battery, containing a metal composite hydroxide, whereinthe metal composite hydroxide is in a form of a particle having a core-shell structure whose surface is coated with an iron compound,the core-shell structure is constituted by a core portion and a shell portion,the core portion contains nickel and aluminum as metal elements,the shell portion contains iron as a metal element,when a composition of the core portion is represented by Ni(1-x)Alx(OH)2,0.01≤x≤0.2 is satisfied,anda molar ratio (M2/M1) between a molar amount M1 of the metal element in the core portion and a molar amount M2 of the metal element in the shell portion satisfiesM2/M1=1/100 to 1/5.