Ternary Cathode Battery with Protective Coating for High-Temperature Stability
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Solution Overview
Problem
Ternary cathode-active materials in lithium rechargeable batteries face issues such as ion dissolution, metal dendrite growth, and internal short circuits due to high temperatures, leading to voltage drops and reduced battery life, which are not cost-effective compared to traditional lithium cobalt oxide materials.
Innovation Solution
A rechargeable battery design incorporating a ternary cathode-active material with a specific compound formula, an electrolyte containing succinonitrile, halogenated ethylene carbonate, and vinyl ethylene carbonate, and a lithium salt concentration optimized to prevent ion dissolution and dendrite formation, ensuring improved lifespan and high-temperature storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ternary cathode-active material is used to reduce production cost, then production cost is reduced, but metal ion dissolution and dendrite growth occur leading to internal short circuits
Solution Approach 1:
A coating layer comprising fluorinated cyclic carbonate and vinylene carbonate is formed on the surface of the ternary cathode-active material. This coating layer acts as an intermediary barrier that prevents direct contact between the electrolyte and metal ions (Ni, Co, Mn), thereby preventing ion dissolution and dendrite growth while maintaining the cost benefits of ternary materials
Solution Approach 2:
The patent modifies the surface chemistry of the cathode-active material by introducing specific coating materials (fluorinated cyclic carbonate and vinylene carbonate) with controlled thickness (5-50 nm). This parameter change creates a protective interface that fundamentally alters the electrochemical stability without changing the bulk composition of the ternary material
2Ease of manufacture
If ternary cathode-active material is used to reduce cobalt content, then production cost is reduced, but discharge voltage is lower compared to LCO-based materials
Solution Approach 1:
The patent optimizes the composition ratios of Ni, Co, and Mn in the ternary cathode-active material along with the coating layer composition to achieve a balance between discharge voltage and production cost. The coating layer also improves electrochemical stability that enhances voltage characteristics
3Power
If battery capacity is increased to compensate for low discharge voltage, then electric power equivalent to LCO is achieved, but battery life and high-temperature storage performance deteriorate
Solution Approach 1:
The coating layer acts as a protective intermediary that stabilizes the cathode-active material during charge-discharge cycles and high-temperature storage. This prevents degradation mechanisms that would otherwise limit battery life, enabling the use of higher-capacity ternary materials without sacrificing durability
Solution Approach 2:
The coating layer is formed on the cathode-active material surface before battery assembly and operation. This preliminary protective action prevents ion dissolution and structural degradation from occurring during initial cycling and high-temperature storage, thereby extending battery life
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 excellent lifespan and high-temperature storage performance while maintaining a low production cost, comparable to traditional lithium cobalt oxide batteries, thus addressing the limitations of ternary cathode-active materials.
Implementation Method 1
the electrolyte includes a lithium salt, a non-aqueous organic solvent, 0.5 weight % to 5 weight % of succinonitrile, 1 weight % to 10 weight % of halogenated ethylene carbonate and 1 weight % to 5 weight % of vinyl ethylene carbonate
Implementation Method 2
reduction of the dissolved metal ions at the anode surface leading to metal dendrite growth causing metal dendrite penetration of a separator
Implementation Method 3
the grown dendrite may penetrate into a thin (~10 to 20 μm) polyolefin separator film, which in turn may lead to problems associated with the occurrence of a micro short circuit inside the battery
Implementation Method 4
The electrolyte includes a lithium salt, a non-aqueous organic solvent
Data Source
Figure 1A
Figure 1B
AI summary
A rechargeable battery comprising an anode, a cathode which includes a ternary cathode-active material, a separator interposed between the cathode and the anode, an electrolyte, and a housing enclosing the electrolyte, the anode, and the cathode, wherein the electrolyte includes a lithium salt, a non-aqueous organic solvent, about 0.5 weight % to 5 weight % of succinonitrile, and at least one of about 1 weight % to 10 weight % of halogenated ethylene carbonate and about 1 weight % to 5 weight % of vinyl ethylene carbonate.