Lithium Battery Coated Positive Electrode High Voltage Cycle Life
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Solution Overview
Problem
Rechargeable lithium batteries face issues with volume change and detachment of active mass materials during charge and discharge at high temperatures and high voltages, leading to poor cycle-life characteristics.
Innovation Solution
A rechargeable lithium battery design incorporating a negative electrode with a carbon-based negative active material and a positive electrode with polyacrylonitrile as a binder, capable of fully charging at 4.3V or more, along with a non-aqueous electrolyte, which includes a manganese-based lithium oxide positive active material and oxalic acid to enhance binding properties and prevent metal ion elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage (4.3V or more) and high temperature charging is used to increase power output, then power is improved, but volume change and detachment of active mass materials occur leading to poor cycle-life
Solution Approach 1:
A coating layer comprising at least one of a metal oxide, metal hydroxide, metal oxyhydroxide, metal carbonate, or metal oxy carbonate is applied to the surface of the positive active material particles. This coating layer acts as an intermediary protective barrier between the high voltage/temperature environment and the active mass materials, preventing volume change and detachment while allowing the battery to maintain high power output at 4.3V or more
Solution Approach 2:
The invention changes the surface parameters of the positive active material by applying a coating layer with specific composition and thickness (0.1 nm to 100 nm). This parameter change protects the underlying active materials from degradation during high voltage and high temperature operation, thereby improving cycle-life characteristics while maintaining power output
2Power
If high voltage charging (4.3V or more) is used to improve power performance, then power is improved, but metal ion elution and HF generation increase reducing battery stability
Solution Approach 1:
The coating layer converts the potentially harmful high voltage environment into a beneficial protective mechanism. By applying the coating layer comprising metal oxides, hydroxides, or related compounds, the battery can operate at high voltages (4.3V or more) without experiencing metal ion elution or HF generation, as the coating layer stabilizes the surface and prevents harmful chemical reactions
Solution Approach 2:
The coating layer serves as an intermediary barrier that prevents direct contact between the electrolyte and the positive active material surface during high voltage operation. This intermediary layer blocks the pathways for metal ion elution and HF generation while still allowing lithium ion transport, thus enabling high power output without harmful 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 battery exhibits improved cycle-life characteristics by reducing volume change and detachment of active mass materials, maintaining high voltage performance, and suppressing HF generation, thereby enhancing high-temperature storage and cycle performance.
Implementation Method 1
Batteries generate electric power using electrochemical reaction materials (referred to hereinafter simply as 'active materials') at a positive electrode and a negative electrode
Implementation Method 2
lithium rechargeable batteries which generate electrical energy from changes of chemical potential during the intercalation/deintercalation of lithium ions at the positive and negative electrodes
Implementation Method 3
A rechargeable lithium battery design incorporating a negative electrode with a carbon-based negative active material and a positive electrode with polyacrylonitrile as a binder, capable of fully charging at 4.3V or more
Implementation Method 4
along with a non-aqueous electrolyte, which includes a manganese-based lithium oxide positive active material and oxalic acid to enhance binding properties and prevent metal ion elution
Data Source
AI summary
A rechargeable lithium battery that includes a negative electrode including a negative active material; a positive electrode including polyacrylonitrile and a positive active material which is capable of fully charging at about 4.3V or more; and a non-aqueous electrolyte.