Layered Nickel Oxide Cathode Composition for Reduced Self-Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional batteries face challenges in achieving high performance due to limitations in electrochemically active material loading, stability, and reactivity, particularly with high oxidation state transition metal oxides, which can lead to gas evolution, structural issues, and self-discharge, necessitating a more effective electrochemically active cathode material.
Innovation Solution
A non-stoichiometric beta-delithiated layered nickel oxide with a specific chemical formula and structure, characterized by a layered crystal structure with ordered O1-type layer stacking sequences and O3-type layer stacking faults, is used as the electrochemically active cathode material, providing improved stability and reduced oxygen evolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If high oxidation state transition metal oxide is used as electrochemically active cathode material, then battery capacity and service life are improved, but gas evolution and structural integrity issues occur
Solution Approach 1:
A coating layer comprising at least one of a metal oxide, metal hydroxide, metal oxyhydroxide, or metal carbonate is applied to the cathode material. This coating acts as an intermediary barrier between the high oxidation state transition metal oxide and the electrolyte solution, preventing direct harmful interactions that cause gas evolution while allowing electrochemical reactions to proceed. The coating layer specifically suppresses oxygen evolution reaction and maintains structural integrity during charge-discharge cycles.
Solution Approach 2:
The oxidation state of the transition metal oxide is controlled to be +3 or higher (such as Ni³⁺, Ni⁴⁺, Co³⁺, Co⁴⁺, Mn⁴⁺), and the coating material parameters are selected from specific metal oxides, hydroxides, oxyhydroxides, or carbonates. By changing these material parameters and their combinations, the battery achieves higher capacity while the coating prevents the harmful effects associated with high oxidation states.
2Quantity of substance
If higher loading of electrochemically active cathode material is used, then battery capacity and service life are increased, but internal volume constraints are exceeded
Solution Approach 1:
A thin coating layer is applied to the cathode material surface. This thin film provides protective functions (preventing gas evolution, suppressing side reactions, maintaining structural stability) without adding significant volume. The coating enables higher loading of active material within fixed battery dimensions by preventing volume expansion from gas evolution and structural degradation.
3Quantity of substance
If high oxidation state transition metal oxide is used, then battery capacity is improved, but thermodynamic instability and self-discharge rate increase
Solution Approach 1:
The coating layer serves as a protective intermediary that stabilizes the thermodynamically unstable high oxidation state transition metal oxide. It prevents direct contact with the electrolyte solution and other battery components, suppressing self-discharge reactions and maintaining structural integrity during storage and operation, thereby improving reliability without sacrificing capacity.
4Quantity of substance
If high oxidation state transition metal oxide is used, then battery capacity is increased, but reactions with battery components and electrolyte occur
Solution Approach 1:
The coating layer comprising metal oxide, hydroxide, oxyhydroxide, or carbonate acts as a protective barrier that prevents the highly reactive high oxidation state transition metal oxide from reacting with conductive carbon additives, surfactants, separator, and electrolyte solution. This intermediary layer allows the active material to maintain its high capacity while being protected from detrimental side reactions.
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 non-stoichiometric beta-delithiated layered nickel oxide enhances battery performance by increasing gravimetric capacity, reducing self-discharge, and minimizing gas evolution, resulting in improved discharge performance across various discharge rates.
Implementation Method 1
The cathode contains an electrochemically active cathode material that can be reduced. The electrochemically active anode material is capable of reducing the electrochemically active cathode material.
Implementation Method 2
The anode contains an electrochemically active anode material that can be oxidized.
Implementation Method 3
The electrolyte contains ions that flow through the separator between the anode and cathode to maintain charge balance throughout the battery during discharge.
Data Source
AI summary
The invention is directed towards an electrochemically active cathode material for a battery. The electrochemically active cathode material includes a non-stoichiometric beta-delithiated layered nickel oxide. The non-stoichiometric beta-delithiated layered nickel oxide has a chemical formula. The chemical formula is LixAyNi1+a−zMzO2·nH2O where x is from about 0.02 to about 0.20; y is from about 0.03 to about 0.20; a is from about 0.02 to about 0.2; z is from about 0 to about 0.2; and n is from about 0 to about 1. Within the chemical formula, A is an alkali metal. The alkali metal includes potassium, rubidium, cesium, and any combination thereof. Within the chemical formula, M comprises an alkaline earth metal, a transition metal, a non-transition metal, and any combination thereof.