Double hydrophobic layer air cathode used for metal/air battery

Abstract

An air cathode used for a metal / air battery mainly includes a first hydrophobic breathable layer, a second hydrophobic breathable layer, a collector and a catalyst layer which are sequentially layered and superposed; and the first hydrophobic breathable layer porosity is greater than the second hydrophobic breathable layer porosity. Compared with the prior art, the pore structures of the first hydrophobic breathable layer and the second hydrophobic breathable layer in the air electrode are different, on the one hand, air mass transfer at the air electrode side of the metal / air battery can be facilitated, on the other hand, electrolyte leakage can be effectively prevented, electrolyte water evaporation and moisture entering into the air can be reduced, and the battery stability can be improved.

Description

technical field [0001] The invention relates to a cathode for metal-air batteries, in particular to a cathode for metal-air batteries such as magnesium, aluminum and zinc. Background technique [0002] A metal-air battery is an electrochemical reaction device that uses magnesium, aluminum, and zinc metals as the anode active material, oxygen in the air as the cathode active material, and alkaline or neutral brine as the electrolyte solution. Metal-air batteries are one of the most promising green and clean energy sources. [0003] Oxygen reduction reaction occurs on the air electrode of the metal-air battery, and the air cathode is one of the core components that affect its excellent performance. When the metal-air battery uses zinc as the anode fuel, a high-concentration alkaline KOH solution is often used as the electrolyte solution. The volatilization of water can easily cause the electrolyte to dry up; on the other hand, when the battery is used under high humidity con...

AI Technical Summary

Problems solved by technology

When the metal-air battery uses zinc as the anode fuel, a high-concentration alkaline KOH solution is often used as the electrolyte solution. The volatilization of water can easily cause the electrolyte to dry up; on the other hand, when the battery is used under high humidity conditions, the moisture in the air will enter the inside of the battery to dilute the electrolyte, affecting the discharge stability of the battery

In order to solve the above problems, the patent CN101702435A proposes a cathode composed of a multi-layer hydrophobic and air-permeable layer. The air electrode using this electrode structure reduces the evaporation loss of water and improves the stability of the electrode. However, the multi-layer polytetrafluoroethylene coating, The preparation process is complicated. At the same time, if the PTFE coating does not meet a certain uniformity during the processing process, it will directly affect the hydrophobicity of the electrode and affect the stability of the electrode to a certain extent.

Patent CN202067864U proposes an air electrode with a waterproof layer rolled on one side of the gas hydrophobic and breathable layer, which can prevent the volatilization of the electrolyte and the moisture in the air from entering the battery, but increases the electrode resistance to a certain extent, making the air electrode low discharge performance

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