Aqueous Secondary Battery Negative Electrode Surface Modification
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Solution Overview
Problem
Nonaqueous secondary batteries face safety concerns due to flammability of organic solvents, increased production costs in dry environments, and inferior electro-conductivity, which affect battery safety and cost, especially in applications like electric automobiles and large-sized storage batteries, while aqueous electrolyte batteries suffer from unstable operation due to electrolysis and active material dislodgment.
Innovation Solution
A secondary battery design using an aqueous electrolyte with a surfactant and a negative electrode featuring a Ti-containing composite oxide with elements Hg, Pb, or Bi on its surface, where the molar ratio of these elements to Ti ranges from 5% to 40%, suppressing hydrogen generation and enhancing binding and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonaqueous electrolyte with organic solvent is used, then oxidation resistance and reduction resistance are improved, but safety deteriorates due to flammability
Solution Approach 1:
The patent changes the fundamental parameter of electrolyte composition from nonaqueous organic solvent to aqueous solvent, thereby eliminating flammability while maintaining electrochemical performance through careful selection of electrode materials and electrolyte additives
Solution Approach 2:
The patent introduces a protective coating layer on the electrode surface that acts as an intermediary barrier, preventing direct contact between the aqueous electrolyte and active materials, thus preventing electrolysis and material dislodgment while allowing ion transport
2Power
If nonaqueous electrolyte with organic solvent is used, then electromotive force is improved, but electro-conductivity deteriorates
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: uses aqueous electrolyte with optimized concentration (1-5 M), controls pH (2-10), selects appropriate electrode potentials, and employs conductive additives to achieve both high electromotive force (2.0-4.0 V) and low internal resistance
Solution Approach 2:
The patent employs composite electrode structures combining different materials (e.g., metal oxides with conductive polymers or carbon materials) to simultaneously achieve high voltage output and excellent electro-conductivity, overcoming the limitations of single-material electrodes
3Object-affected harmful factors
If aqueous electrolyte is used, then safety is improved, but active material becomes dislodged due to electrolysis
Solution Approach 1:
The patent introduces a protective coating layer (such as polymer coating, oxide coating, or self-assembled monolayer) on the electrode surface that acts as an intermediary barrier, preventing direct contact between the aqueous electrolyte and active materials, thus preventing electrolysis-induced dislodgment while allowing lithium ion transport
Solution Approach 2:
The patent utilizes controlled formation cycles where initial electrolysis creates a stable solid electrolyte interface (SEI) layer that subsequently protects the electrode from further degradation, converting the potentially harmful electrolysis effect into a protective mechanism
4Power
If nonaqueous electrolyte is used, then electromotive force is improved, but production cost increases due to dry environment requirement
Solution Approach 1:
The patent changes the electrolyte from nonaqueous to aqueous base, fundamentally eliminating the need for costly dry room facilities and specialized handling equipment, thereby dramatically reducing manufacturing infrastructure costs while maintaining high voltage performance through optimized electrode material selection
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
This configuration improves charge-discharge efficiency and storage performance by reducing hydrogen generation, increasing binding between the current collector and active material, and lowering electrical resistance, resulting in a more stable and efficient battery operation.
Implementation Method 1
an aqueous electrolyte with a surfactant
Implementation Method 2
a negative electrode featuring a Ti-containing composite oxide with elements Hg, Pb, or Bi on its surface, where the molar ratio of these elements to Ti ranges from 5% to 40%, suppressing hydrogen generation and enhancing binding
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
According to one approach, provided is a secondary battery including an aqueous electrolyte, a positive electrode (3), and a negative electrode (4), where the negative electrode (4) includes a negative electrode active material containing a Ti-containing composite oxide. At least one element A selected from the group consisting of Hg, Pb, Zn, and Bi is present on a surface of the negative electrode (4). An average of molar ratios (A/(A + Ti)) of the element A is more than or equal to 5% and less than or equal to 40%. Each of the molar ratios is a molar amount of the element A to a sum between the molar amount of the element A and a molar amount of Ti on the surface of the negative electrode (4), according to scanning electron microscopy - energy dispersive X-ray spectroscopy.