Nickel-Rich Core-Shell Cathode for Solid-State Interface Stability

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Solution Overview

Problem

Lithium-ion batteries with nickel-rich positive electrodes face interfacial compatibility and stability issues with solid-state electrolytes, leading to capacity degradation and increased resistance due to passivating interphase formation and structure instabilities.

Innovation Solution

A nickel-rich material with a heterogeneous structure comprising a core of nickel-cobalt-manganese and a shell of nickel-cobalt-aluminum, optionally with a buffer layer, is used to enhance interfacial compatibility and stability with sulfide-based solid-state electrolytes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If nickel-rich electroactive materials are used to improve capacity capability, then capacity capability is improved, but interfacial compatibility and stability with solid-state electrolytes deteriorate

Engineering Contradiction:

Improvecapacity capabilityVSAvoidinterfacial compatibility and stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent employs a core-shell composite structure where the core is nickel-rich (high capacity) and the shell is aluminum-rich (high stability). This composite material approach allows the electrode to simultaneously achieve high capacity from the nickel-rich core and good interfacial stability from the aluminum-rich shell, resolving the contradiction between capacity and reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies different material compositions to different regions of the electrode particle. The core region uses nickel-rich material for high capacity, while the shell region uses aluminum-rich material for high stability. This local differentiation of material properties allows each region to optimize for its specific function, resolving the capacity-stability trade-off.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If nickel-rich materials are used to enable additional lithium extraction, then lithium extraction capability is improved, but structural stability deteriorates

Engineering Contradiction:

Improvelithium extraction capabilityVSAvoidstructural stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The core-shell composite structure enables the core to perform lithium extraction while the shell maintains structural integrity. The aluminum-rich shell acts as a protective framework that prevents structural degradation during lithium insertion/extraction cycles, allowing high lithium extraction capability without compromising structural stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The aluminum-rich shell is formed beforehand to provide structural support and protection. This pre-formed stable shell cushions and protects the nickel-rich core from structural degradation that would normally occur during repeated lithium extraction and insertion, enabling high lithium extraction capability while maintaining structural stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If solid-state electrolyte is used to physically separate electrodes, then separator requirement is eliminated, but passivating interphase formation occurs causing capacity degradation

Engineering Contradiction:

Improveseparator requirementVSAvoidcapacity retention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The aluminum-rich shell acts as an intermediary layer between the nickel-rich electrode core and the solid-state electrolyte. This intermediate shell prevents direct harmful interaction between the electrode and electrolyte, avoiding passivating interphase formation while still allowing ionic transport, thus maintaining capacity retention without requiring an additional separator.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potential harm of direct electrode-electrolyte contact (which causes passivating interphase formation) into a benefit by using the aluminum-rich shell to mediate the interaction. The shell transforms the harmful direct contact into a controlled indirect interaction, preventing capacity degradation while maintaining the simplicity of the solid-state battery design.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12512471B2Positive electroactive materials for all-solid-state battery

Publication Date: 2025.12.30 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

The present disclosure provides a positive electroactive material for an electrochemical cell that cycles lithium ions. The positive electroactive material includes a nickel-rich material including a plurality of solid-state particles. Each solid-state particle has a heterogeneous structure that includes a core and a shell that at least partially coats the core. The core includes a nickel-cobalt-manganese material, and the shell includes a nickel-cobalt-aluminum material. When the nickel-rich material is represented by LiNi(1-x-y-z)CoxMnyAl2O2, the nickel-cobalt-manganese material is represented by LiNi(i-x″-(y/a))Cox″Mn(y/a)O2, and the nickel-cobalt-aluminum material is represented by LiNi(i-x″-(z/b))Cox″Al(z/b)O2, where (i) 1-x-y-z>0.5, (ii) a+b=1, (iii) zx″+bx″=x, and (iv) 1-x″-(y/a)>1-x″-(z/b). In certain variations, the core and the shell define a base structure, and the heterogeneous structure further includes a buffer layer that at least partially coats the base structure.