Lithium-Ion Battery Formation with Solid-State Anode Coating
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Solution Overview
Problem
High-nickel silicon-oxygen system batteries face safety issues due to thermal runaway, primarily caused by heat release at the positive/negative electrode interface and crosstalk reactions between electrodes.
Innovation Solution
A lithium-ion battery with a negative electrode sheet featuring a solid-state electrolyte coating layer, where the molar ratio of high-valence to low-valence metal elements is 1:0.1 to 1:1, and a two-step formation method to create a protective SEI film with a sandwich structure, enhancing mechanical strength and suppressing crosstalk reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-nickel silicon-oxygen system batteries are used to achieve higher mass energy density, then energy density is improved, but safety issues arise due to thermal runaway caused by heat release at the electrode interface and crosstalk reactions
Solution Approach 1:
A solid-state electrolyte coating layer is introduced as an intermediary between the positive and negative electrodes. This coating layer acts as a physical barrier that prevents direct contact and crosstalk reactions between electrodes, thereby eliminating the thermal runaway pathway while maintaining the high energy density benefits of the silicon-oxygen negative electrode system
Solution Approach 2:
The solid-state electrolyte coating layer is constructed as a composite material containing high-valence metal elements (such as Ti4+, Nb5+, Ta5+) and low-valence metal elements (such as Li+, Na+, K+). This composite structure provides both the protective barrier function and the necessary ionic conductivity for lithium ion transport, resolving the contradiction between safety and electrochemical performance
2Reliability
If a solid-state electrolyte coating layer is formed on the negative electrode surface to suppress crosstalk reactions, then safety is improved, but the complexity of electrode preparation increases
Solution Approach 1:
The solid-state electrolyte coating layer is prepared in advance on the negative electrode surface before battery assembly. This preliminary action ensures that the protective layer is already in place to prevent crosstalk reactions from the outset, eliminating the need for additional safety measures during battery operation and simplifying the overall manufacturing process
Solution Approach 2:
The coating layer utilizes specific molar ratios of high-valence to low-valence metal elements (1:0.1 to 1:1) to optimize both the protective性能和 ionic conductivity. By controlling these compositional parameters, the coating achieves effective protection against crosstalk reactions while maintaining necessary electrochemical performance, balancing safety improvements with preparation feasibility
3Stability of the object's composition
If a protective coating layer is applied to prevent transition metal ion deposition on the negative electrode, then electrode stability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The solid-state electrolyte coating layer serves as an intermediary barrier that prevents transition metal ions from the positive electrode from migrating to and depositing on the negative electrode. This intermediary layer maintains electrode compositional stability while using a relatively simple coating process that can be integrated into existing manufacturing workflows
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 solution effectively suppresses crosstalk reactions, prevents transition metal ion deposition, reduces electrolyte consumption, and improves cycle life by forming a protective SEI film with enhanced mechanical strength and thermal stability.
Implementation Method 1
In the first step of the formation process, an electrolyte solution forms a solid-state ion conductor film (SEI film) on a surface of a negative electrode active coating layer
Implementation Method 2
In the second step of the formation process, the solid-state electrolyte coating layer is reduced in situ to form a rigid inorganic solid-state ion conductor film
Data Source
AI summary
A lithium-ion battery and a method of preparing the same are provided. The lithium-ion battery includes a cell and an electrolyte solution, and the cell includes a negative electrode sheet. The negative electrode sheet includes a negative electrode current collector, an active coating layer disposed on a surface of the current collector, and a protective coating layer disposed on a surface of the active coating layer. The protective coating layer is a solid-state electrolyte coating layer. The electrolyte solution contains a film-forming agent. The method includes the following steps. After the cell is placed in a casing and the electrolyte solution is injected, formation is performed on the lithium-ion battery. The formation includes: S1, performing charging to 3.4V to 3.75V with a constant current rate of 0.02C to 0.04C; and S2, performing charging to 3.75V to 4.25V with a constant current rate of 0.05C to 0.3C.