直接硼氢化钠燃料电池在不同运行条件下的放电特性研究

Discharge Characteristics of Direct Sodium Borohydride Fuel Cells under Different Operation Conditions

研究了以Ni粉为阳极催化剂、Pt/C为阴极催化剂、Nafion117为电解质膜的直接硼氢化钠燃料电池(DSBFC),通过电池的极化曲线、功率密度曲线,研究了DSBFC在不同阴极供料方式、不同温度和硼氢化钠浓度等条件下的放电特性。结果表明:阴极通加湿氧气有利于提高电池性能;随着硼氢化钠浓度的增加和温度的升高,电池性能都会提高;50℃时NaBH4浓度对电池性能影响更大,NaBH4浓度为0.5mol·L-1时温度对电池的性能影响更大。通过电流-时间曲线考察了电池的库仑效率及短期运行的稳定性。结果显示:在高温时电池放电相对平稳;NaBH4浓度越大,库仑效率越低;温度对库仑效率影响不大。以加湿氧气为氧化剂、硼氢化钠浓度为1.0mol·L-1、电池运行温度为80℃时,DSBFC性能最佳,最大功率密度为39.5mW·cm-2(0.5V)。

A direct sodium borohydride fuel cell （DSBFC） employing Ni powder as anode catalyst, carbon supported Pt as cathode catalyst and Nafion117 as electrolyte membrane was fabricated. The discharge characteristics of the prepared DSBFC under different operation conditions, such as cathode feeding mode, cell temperature, and the concentration of sodium borohydride, were studied by measuring its polarization curves and power density curves. It is shown that feeding humidified O2 to cathode is beneficial to the performance of the cell. A better cell performance could be obtained by increasing the NaBH4 concentration and raising the temperature. The effect of NaBH4 concentration on cell performance is greater at 50℃ than that at 20℃ and 80 ℃. Similarly, temperature has a greater influence on the cell performance when NaBH4 concentration is fixed at 0.5 mol·L^-1. The coulombic efficiency and short-time operating stability of the DSBFC were investigated by I-t curves. The I-t curve is smoother at higher temperature than that at lower temperatures. The higher the NaBH4 concentration, the lower the coulombic efficiency. Temperature has a weak effect on the coulombic efficiency of fuel. The peak power density of the prepared DSBFC （0.5 V） is 39.5 mW·cm^-2 with feeding humidified oxygen and NaBH4 concentration of 1.0 mol·L^-1 at 80℃.