Spinel Oxide Cathode Composition for Higher Charge-Discharge Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Spinel-type alkali metal-containing oxides have room for improvement regarding charge/discharge capacities.
Innovation Solution
An alkali metal-containing oxide with a spinel structure and specific composition (1.1<x≤2.8, 0.8≤a≤1.9, 0.05<b≤0.6, 1.0≤a+b<2.0, 0≤c<0.2, 0≤d<1.0, 0≤e<1.0) exhibits a peak in the X-ray diffraction chart within 40° to 45° at 2θ, and is used in a battery with a lithium-metal auxiliary electrode and electrolytic solution, charged to 4.8 V and discharged to 1.5 V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If spinel-type alkali metal-containing oxides are used as positive electrode active substances, then the battery structure is established and basic electrochemical function is achieved, but the charge/discharge capacity is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional ratios of alkali metals to transition metals and oxygen content in the spinel-type oxide. By adjusting these stoichiometric parameters within specific ranges, the charge/discharge capacity is significantly improved while maintaining electrochemical stability and structural integrity during cycling
Solution Approach 2:
The patent employs composite materials by creating spinel-type alkali metal-containing oxides with multi-element compositions involving alkali metals (Li, Na, K), transition metals (Mn, Ni, Co, Fe), and other elements (Ti, V, Cr). This composite approach combines the advantages of different elements to achieve high capacity while maintaining structural stability
2Quantity of substance
If the composition ratio of alkali metal ions per four oxygens is increased beyond one, then the theoretical capacity is enhanced, but the structural stability and electrochemical performance deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the alkali metal to oxygen ratio within a specific range (greater than 1.0 but controlled to maintain stability). This precise parameter control allows the structure to accommodate excess alkali metals without collapsing, achieving high capacity while preserving spinel structure integrity
Solution Approach 2:
The patent applies local quality by distributing alkali metals and transition metals in specific crystallographic sites within the spinel structure. Alkali metals occupy tetrahedral sites while transition metals occupy octahedral sites, creating local compositional variations that enhance both capacity and structural stability
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 alkali metal-containing oxide demonstrates excellent charge/discharge capacity and coulombic efficiency, enhancing the performance of electrodes and batteries.
Implementation Method 1
Secondary batteries performing charging and discharging by migrating alkali metal ions between the positive electrode and the negative electrode are known
Implementation Method 2
in an X-ray diffraction chart measured regarding the alkali metal-containing oxide at 25° C. using a CuKα ray, a peak having a half width of 0.5° to 5° at 2θ is observed within a range of 40° to 45° at 2θ
Data Source
AI summary
An alkali metal-containing oxide of the present disclosure has a spinel structure and a composition represented by the following formula (1). In an X-ray diffraction chart measured at 25° C. using a CuKα ray, a peak having a half width of 0.5° to 5° is observed within a range of 40° to 45°.(In the formula (1), 1.1<x≤2.8, 0.8≤a<1.9, 0.05<b≤0.6, 1.0≤a+b<2.0, 0≤c<0.2, 0≤d<1.0, 0≤e<1.0,A is an alkali metal element, M′ is at least one element from Ti, Cr, Mn, Fe, Co, Ni and Cu, M″ is at least one from Si, P, S, Ge and V, Z is an element of Group II to Group XVI except oxygen, M′ and M″, and X is a halogen element.)