Study On Films Modification On Titanium Bipolar Plates For Regenerative Fuel Cell Deposited By AIP

With the continuous development of modern technology and our pursuit for high quality living environment, the trend of displacement of conventional fossil fuel by a new kind of clean, regenerative, and environment-friendly energy source is under going, and it is also inevitable. As a new kind of energy source, hydrogen energy enjoy high favor among people, because its high energy conversion ratio,friendly to environment and regeneration characters. As an important form of regenerative energy, Fuel Cell (FC) has its own feature. Especially for Regenerative Fuel Cell (RFC), it can fully use solar energy, wind energy etc.. regenerative energy to store the energy with the form of hydrogen, when it needs to consume energy, the device can change the chemical energy of hydrogen directly into electricity, it has the character of high energy conversion ratio and friendly to environment, it has a extensive prospects and value on the use of transportation, portable energy systems and energy storage devices for spacecraft.As an important part of RFC, bipolar plate accounts for the majority of battery weight and cost, the property of bipolar plate has a direct impact on fuel cell's performance. The ideal bipolar plate must have a good conductivity and mechanical processing properties, and meanwhile it must have remarkable anticorrosion property. So, it's important for improving fuel cell overall properties to enhance the bipolar plate properties. In this paper we focus on the passive film formed on the surface of titanium bipolar plate for RFC, it contributes to the reduction of the conductivity property.The metal has good conductivity, because it owns a large number of movable free electrons. However, the chemistry corruption and electrochemistry corruption are the processes that the metal atom loses its free electrons and produces metallication. So the anti-corrodibility property and conductivity are incompatible. Except for some kinds of heavy metals such as Au and Ag, it is difficult to obtain a kind of metal which both has good conductivity and anti-corrodibility property.The author deposits a series of Ti-Ag alloy films, TiN-Pd/TiN composite multilayer films and Ti-N-Ag films on titanium bipolar plate used for regenerative fuel cell by Pulse Bias Arc Ion Plating equipment designed by this laboratory, Film surface morphology, structure, the contact resistance, electrochemical corrosion property and water contact angle are investigated. The result shows three kinds of deposited films have an improvement on the conductivity and anticorrosion properties. Among them, the conductivity property improved significantly, and comparing with the untreated titanium bipolar plate, contact resistance decreased more than an order of magnitude, already exceeds the application standard.