Surface-Modified Lithium Transition Metal Oxide for Low-Temperature Output
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Solution Overview
Problem
Conventional nonaqueous electrolyte secondary batteries, particularly those using lithium transition metal oxides with nickel as the main transition metal component, face challenges in enhancing output characteristics at low temperatures.
Innovation Solution
A nonaqueous electrolyte secondary battery with a positive electrode active material comprising lithium transition metal oxide particles where a first compound from Group IV or V elements is sintered onto the surface and a second compound from Group VI elements is attached, enhancing the interface with the electrolyte and reducing reaction resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium transition metal oxides containing nickel are used as positive electrode active materials, then high capacity and high output are achieved, but output characteristics at low temperatures deteriorate
Solution Approach 1:
The patent applies local quality by creating a surface-modified positive electrode active material where the outer surface has different composition and properties from the core. Specifically, the surface is enriched with nickel and cobalt while the interior maintains the original lithium transition metal oxide composition, providing temperature-dependent performance optimization
Solution Approach 2:
The patent uses composite materials by combining lithium transition metal oxide particles with a surface coating layer containing nickel oxide and cobalt oxide. This composite structure allows the core material to provide high capacity while the surface layer enhances low-temperature output characteristics through improved ionic and electronic conductivity
2Power
If niobium compound is sintered on the surface of positive electrode active material, then output characteristics are enhanced, but low-temperature output characteristics remain insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the surface composition parameters of the positive electrode active material. The surface layer contains specific ratios of nickel oxide (40-80 wt%) and cobalt oxide (20-60 wt%) to optimize electrical conductivity and ionic transport at low temperatures, representing a deliberate change in compositional parameters
3Stability of the object's composition
If surface modification with nickel oxide containing various elements is applied, then thermal stability improves, but low-temperature output characteristics are not sufficiently enhanced
Solution Approach 1:
The patent applies local quality by concentrating nickel and cobalt oxides specifically at the surface layer of the positive electrode active material particles. This localized enrichment creates a surface with high electrical conductivity and low reaction resistance, while the bulk material maintains its thermal stability properties
Solution Approach 2:
The patent creates a surface layer that copies the beneficial properties of nickel-rich materials (high conductivity) while avoiding their drawbacks (thermal instability). The controlled surface composition mimics the advantages of nickel-based materials without sacrificing the overall thermal stability of the lithium transition metal oxide core
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 configuration significantly improves output characteristics under low-temperature conditions by forming a solid solution with the lithium transition metal oxide and reacting with residual lithium compounds, thereby promoting charge transfer reactions.
Implementation Method 1
a first compound containing at least one element Ma selected from the group consisting of Group IV elements and Group V elements is sintered to a portion of the surface of the lithium transition metal oxide particles
Implementation Method 2
a second compound containing at least one element Mb selected from the group consisting of Group VI elements is attached to a portion of the surface of the lithium transition metal oxide particles
Implementation Method 3
a first compound containing at least one element Ma selected from the group consisting of Group IV elements and Group V elements is sintered to a portion of the surface of the lithium transition metal oxide particles
Data Source
AI summary
A nonaqueous electrolyte secondary battery of the invention includes a positive electrode, a negative electrode and a nonaqueous electrolyte, the positive electrode including lithium transition metal oxide particles as a positive electrode active material, the lithium transition metal oxide particles containing nickel as a main transition metal component and being such that a first compound containing at least one element Ma selected from the group consisting of Group IV elements and Group V elements is sintered to a portion of the surface of the lithium transition metal oxide particles, the first compound having a composition different from that of the lithium transition metal oxide particles, the positive electrode further including a second compound containing at least one element Mb selected from the group consisting of Group VI elements, the second compound having a composition different from that of the lithium transition metal oxide particles.