Composite Cathode Morphology for High Energy and Long Cycle Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium ion battery cathode materials face challenges in achieving high capacity, low cost, and environmental friendliness while being compatible with existing manufacturing facilities, with Mn-rich cathodes suffering from poor rate capability and voltage fade, and LFP cathodes having lower capacity and higher manufacturing costs.
Innovation Solution
A composite cathode material comprising polycrystalline and polyhedral particles with tailored Mn and Ni compositions, where the polyhedral particles are localized on the surface or intermixed with the polycrystalline particles, enhancing grain boundary enrichment with Co or Al, resulting in improved cycle life and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Mn-rich cathodes are used to reduce cost and improve environmental friendliness, then manufacturing cost decreases and environmental impact is reduced, but rate capability and voltage stability deteriorate
Solution Approach 1:
The patent applies local quality by creating a composite structure where Mn-rich material (low cost, environmentally friendly) forms the core particles, while a small amount of Ni-Co-rich material is localized at the grain boundaries and surfaces. This local enrichment of stabilizing elements at critical interfaces maintains rate capability and voltage stability without increasing overall material cost, as the expensive elements are concentrated only where needed for performance.
Solution Approach 2:
The patent employs composite materials by combining Mn-rich layered oxide particles with Ni-Co-rich spinel particles to form a core-shell composite structure. The Mn-rich core provides low cost and environmental benefits, while the Ni-Co-rich spinel shell at grain boundaries provides the necessary rate capability and voltage stability, resolving the contradiction between cost and performance.
2Quantity of substance
If Ni and Co content is increased to achieve high capacity, then capacity increases, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by concentrating Ni and Co elements specifically at the grain boundaries and particle surfaces rather than distributing them uniformly throughout the bulk material. This localized enrichment maintains high capacity by ensuring these expensive elements are present where they most effectively contribute to electrochemical performance, while minimizing their overall quantity and thus manufacturing cost.
Solution Approach 2:
The patent changes the compositional parameters by using Mn-rich bulk material (reducing expensive element content) while maintaining high capacity through the spinel phase formation at grain boundaries. The spinel structure with specific Ni-Co ratios provides high capacity without requiring high overall concentrations of these expensive elements in the bulk material.
3Ease of manufacture
If LFP materials are used to reduce cost, then manufacturing cost decreases, but capacity and energy density decrease
Solution Approach 1:
The patent uses composite materials by combining Mn-rich layered oxide (providing high capacity similar to NMC622) with Ni-Co-rich spinel particles at grain boundaries (enhancing performance). This composite structure achieves both low manufacturing cost (comparable to LFP) and high capacity (>200 mAh/g), overcoming the capacity limitation of pure LFP materials.
Solution Approach 2:
The patent changes the compositional parameters by optimizing the Mn content in the bulk (30-80 at%) and the Ni-Co content at grain boundaries, creating a material with capacity comparable to or exceeding NMC622 while maintaining manufacturing costs similar to LFP. The spinel phase formation and grain boundary engineering enable high capacity without requiring expensive high-Ni bulk compositions.
Data Source
AI summary
Provided are electrochemically active composite materials that include a first particle comprising a first composition optionally of Li1+aMO2+b (Formula I) where −0.3≤a≤0.3 and −0.3≤b≤1.3 and where M optionally includes 30 at % to 80 at % Mn and 30 at % to 75 at % Ni, the first particle formed of a polycrystalline morphology having a plurality of crystallites and a grain boundary between adjacent crystallites; and a second particle comprising a second composition optionally of Li1+cM′2O4+d (Formula II) where −0.1≤c≤0.3 and −0.2≤d≤0.2, wherein M′ comprises Mn at about 75 at % to about 100 at %, wherein said second composition or a portion thereof with a spinel structure and in the form of a three dimensional polyhedron; and wherein said second particle is within, on or about a surface of said first particle.