A graphite microcrystalline carbon coating for a metal bipolar plate of a fuel cell and application thereof

Abstract

The invention relates to a graphite microcrystalline carbon coating for a metal bipolar plate of a fuel cell and application thereof, wherein the coating is coated on the surface of the metal bipolarplate, the graphite microcrystalline carbon coating is a graphite-like coating, and the coating comprises 5-50 wt% of graphite microcrystalline, and has good compactness. On the basis of conventionalmagnetron sputtering technology, carbon coatings with high conductivity, corrosion resistance and stability can be prepared by changing the energy of deposited particles by changing the target sputtering power, sputtering magnetic field strength and coating deposition temperature, thus changing the structure of carbon coatings. In accordance with that prior art, As that preparation cost of the coat is not increased, the contact resistance between the metal bipolar plate of the fuel cell and the gas diffusion lay can be reduced, the corrosion resistance of the carbon coating in the acidic environment of the fuel cell and the stability of the conductivity after long-time testing can be improved, and the invention has important significance for promoting the commercialization process of the fuel cell.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, and relates to a graphite microcrystalline carbon coating for metal bipolar plates of fuel cells and its application. Background technique [0002] Fuel cells use hydrogen as an energy source, which has the characteristics of high efficiency and cleanliness, and has broad application prospects in many fields. Among them, the bipolar plate is one of the important components of the fuel cell, and its performance restricts the commercialization process of the fuel cell. Metal materials have become the main materials for fuel cell bipolar plates because of their advantages such as good mechanical properties, corrosion resistance and low cost. [0003] Fuel cell metal bipolar plates generally work in a high-temperature, high-humidity acidic environment with a pH value of 2-5 and a temperature of 70-100°C. In this environment, the surface of the metal material serving in this environment will passi...

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Problems solved by technology

[0004] Carbon coatings have good electrical conductivity and corrosion resistance, but the actual on-board working conditions of fuel cell vehicles are more complicated. Typical working conditions such as low-load idling, cyclic loading, start-stop, etc. will lead to attenuation of carbon coating performance, while fuel cell vehicles The service life of the battery also requires the coating to have good stability and durability

Chinese patent CN101640276A discloses an amorphous carbon coating on a fuel cell bipolar plate, which has good electrical conductivity and corrosion resistance, but the data show that its contact resistance is greater than 10mΩ·〖cm under the working pressure of the bipolar plate 〗^2, and the electrical conductivity of the coating is unknown after a long time electrochemical test; Chinese patent CN 107978770A discloses a method for preparing a carbon coating on the surface of a fuel cell metal separator using the PECVD method, and the coating still exists Defects with high contact resistance under the operating compression force of the separator, and the durability of the coating is unknown

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