Anode-Free Secondary Battery With Layered Cathode Chemistry
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Solution Overview
Problem
Existing secondary batteries face issues such as environmental pollution, high production cost, low energy density, and low working voltage due to the use of transition metal elements and graphite as both positive and negative active materials.
Innovation Solution
A secondary battery design that uses graphite or other materials in a layered crystal structure as a positive active material without a negative active material, utilizing a negative current collector that reacts with cations in the electrolyte, and employs a lithium hexafluorophosphate electrolyte with ethyl methyl carbonate and vinylene carbonate additives to enhance energy density and working voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional coating method is used to form the protective coating layer, then the coating can be applied to the current collector, but the coating thickness cannot be uniformly controlled and the coating process is complex
Solution Approach 1:
The patent replaces conventional mechanical coating methods with an electrochemical coating process. The protective coating layer is formed through electrochemical reactions during battery assembly, where a plating catalyst layer is deposited on the current collector surface through electrocatalytic hydrogen evolution reaction. This substitution achieves uniform coating thickness control without complex mechanical coating equipment or processes.
2Reliability
If the protective coating layer is formed by conventional coating, then coating can be applied, but residual solvent remains and causes safety issues
Solution Approach 1:
The patent replaces solvent-based coating with electrochemical deposition. The protective coating layer is formed through electrochemical reactions without requiring organic solvents. The coating material is deposited directly from ionic species in the electrolyte solution through electroreduction, eliminating residual solvent issues and improving battery safety.
Solution Approach 2:
The electrochemical coating process occurs in an inert electrolyte environment, replacing organic solvents with aqueous or ionic liquid electrolytes that do not pose fire hazards. This creates a safer processing environment and eliminates the safety risks associated with residual organic solvents in the final product.
3Reliability
If no protective coating is applied, then the structure is simple, but the plating catalyst layer cannot be uniformly formed and dendrites grow during charging
Solution Approach 1:
The patent applies preliminary action by forming the plating catalyst layer during the battery assembly process itself, before the battery enters service. The electrochemical coating is performed in-situ during cell formation cycles, preparing the current collector surface with a uniform catalyst layer that prevents dendrite growth during subsequent charging cycles. This preliminary preparation eliminates the need for separate coating steps.
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 achieves a working voltage of about 4.2 V, significantly improving energy density and reducing weight and cost by eliminating the need for a negative active material, while maintaining stable cycling performance.
Implementation Method 1
a plating catalyst layer is formed on a surface of the current collector, the plating catalyst layer promoting an electrocatalytic hydrogen evolution reaction
Data Source
Figure 1~2
Figure 3~4
AI summary
A secondary battery and a preparation method therefor. The secondary battery comprises: a negative pole (1) of the battery, electrolyte (2), a diaphragm (3), a positive pole (4) of the battery, and a battery shell used for packaging, wherein the negative pole (1) of the battery comprises a negative current collector, and does not comprise a negative active material; the positive pole (4) of the battery comprises a positive active material layer (41), the positive active material layer (41) comprises a positive active material, and the positive active material comprises a material having a layered crystal structure; and the electrolyte (2) comprises electrolyte salt and an organic solvent. The main active component of the secondary battery is a material having a layered crystal structure, such that the secondary battery is environmentally-friendly and low in cost; furthermore, a negative active material is not needed by a second battery system, such that the self-weight and cost of the battery are remarkably reduced, and the energy density of the battery is improved; and a reaction principle adopted by the secondary battery significantly increases the working voltage of the battery and further improves the energy density of the battery.