Buffer Interlayers for Membraneless High-Voltage Zinc Batteries
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Solution Overview
Problem
Lithium-ion batteries face safety issues such as explosion and fire hazards due to uncontrolled heat generation, and the mining of cobalt for these batteries poses ethical concerns, while high voltage zinc-manganese dioxide batteries require expensive ion-exchange membranes to operate effectively, limiting their market entry.
Innovation Solution
A membraneless high voltage zinc-anode battery design using a buffer interlayer to separate acid and alkaline electrolytes, eliminating the need for expensive membranes and enhancing safety and toxicity profiles by using earth-abundant, non-toxic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion-exchange membranes are used to separate acid and alkaline electrolytes in high voltage zinc-manganese dioxide batteries, then the battery can operate effectively with decoupled electrolytes, but the cost increases significantly
Solution Approach 1:
The patent replaces expensive ion-exchange membranes with inexpensive cellulose-based separators (like cellophane) that can be easily manufactured and disposed of. These separators, while having shorter operational lifetimes than membranes, provide sufficient separation functionality at a fraction of the cost, enabling commercial viability of high voltage aqueous batteries.
Solution Approach 2:
The patent introduces an intermediary buffer layer between the acid and alkaline electrolytes that prevents direct neutralization reactions. This buffer layer acts as a chemical mediator that maintains pH gradients and allows the battery to operate with decoupled electrolytes using inexpensive separators rather than expensive ion-exchange membranes.
2Device complexity
If acid and alkaline electrolytes are mixed in high voltage zinc-manganese dioxide batteries, then the battery structure is simplified, but immediate neutralization reactions occur preventing operation
Solution Approach 1:
The patent segments the electrolyte system into distinct acid and alkaline compartments separated by a buffer layer and separator. This segmentation prevents direct mixing and neutralization reactions while maintaining the simplicity of an aqueous battery structure, allowing each electrolyte to function optimally in its designated zone.
Solution Approach 2:
The buffer layer serves as an intermediary zone between the acid and alkaline electrolytes, preventing direct contact and neutralization reactions. This intermediary layer allows the battery to maintain a simplified structure without requiring complex mixing prevention mechanisms, as the buffer chemically mediates the interface between the two electrolyte types.
3Use of energy by moving object
If lithium-ion batteries are used for high voltage applications, then high energy density is achieved, but safety hazards such as explosion and fire occur
Solution Approach 1:
The patent uses aqueous electrolytes (water-based) instead of flammable organic electrolytes found in lithium-ion batteries. Water serves as an inert, non-flammable medium that provides high thermal stability and eliminates fire hazards, while still enabling high voltage operation through the decoupled acid-alkaline electrolyte system with buffer layers.
Solution Approach 2:
The patent changes the fundamental parameter of electrolyte composition from organic solvents to aqueous solutions, and from single-phase to decoupled acid-alkaline phases. This parameter change fundamentally alters the safety profile by eliminating flammability while maintaining high energy density through the high voltage enabled by pH gradient management via buffer layers.
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 membraneless battery achieves high voltage discharge characteristics without expensive membranes, ensuring safety and reducing environmental impact, with the buffer interlayer maintaining pH gradients and preventing neutralization reactions, thus enabling long-term high voltage operation.
Implementation Method 1
The one or more buffer interlayers regulate a pH in the battery
Implementation Method 2
at least one of the one or more buffer interlayers comprises a weak acid and its conjugate base; and/or at least one of the one or more buffer interlayers comprises a weak base and its conjugate acid
Implementation Method 3
The catholyte has a pH of less than 4, and the anolyte has a pH of greater than 10. The one or more buffer interlayers regulate a pH in the battery
Data Source
AI summary
A membraneless battery comprising a cathode comprising a cathode electroactive material; an anode comprising an anode electroactive material; a catholyte in contact with the cathode, wherein the catholyte is not in contact with the anode; an anolyte in contact with the anode, wherein the anolyte is not in contact with the cathode; and one or more buffer interlayers disposed between the anolyte and the catholyte. The catholyte has a pH of less than 4, and the anolyte has a pH of greater than 10. The one or more buffer interlayers regulate a pH in the battery. The anode electroactive material comprises a Zn electroactive material. At least one of the one or more buffer interlayers comprises a weak acid and its conjugate base; and/or at least one of the one or more buffer interlayers comprises a weak base and its conjugate acid.