Ionic thermal up-diffusion in nanofluidic salinity-gradient energy harvesting  

作　　者：Rui Long Zhengfei Kuang Zhichun Liu Wei Liu 

机构地区：[1]School of Energy and Power Engineering,Huazhong University of Science and Technology

出　　处：《National Science Review》2019年第6期1266-1273,共8页国家科学评论（英文版）

基　　金：supported by the National Natural Science Foundation of China(51706076 and 51736004)

摘　　要：Advances in nanofabrication and materials science give a boost to the research in nanofluidic energy harvesting.Contrary to previous efforts on isothermal conditions,here a study on asymmetric temperature dependence in nanofluidic power generation is conducted.Results are somewhat counterintuitive.A negative temperature difference can significantly improve the membrane potential due to the impact of ionic thermal up-diffusion that promotes the selectivity and suppresses the ion-concentration polarization;especially at the low-concentration side,which results in dramatically enhanced electric power.A positive temperature difference lowers the membrane potential due to the impact of ionic thermal down-diffusion,although it promotes the diffusion current induced by decreased electrical resistance.Originating from the compromise of the temperature-impacted membrane potential and diffusion current,a positive temperature difference enhances the power at low transmembrane-concentration intensities and hinders the power for high transmembrane-concentration intensities.Based on the system’s temperature response,we have proposed a simple and efficient way to fabricate tunable ionic voltage sources and enhance salinity-gradient energy conversion based on small nanoscale biochannels and mimetic nanochannels.These findings reveal the importance of a long-overlooked element-temperature-in nanofluidic energy harvesting and provide insights for the optimization and fabrication of high-performance nanofluidic power devices.Advances in nanofabrication and materials science give a boost to the research in nanofluidic energy harvesting. Contrary to previous efforts on isothermal conditions, here a study on asymmetric temperature dependence in nanofluidic power generation is conducted. Results are somewhat counterintuitive. A negative temperature difference can significantly improve the membrane potential due to the impact of ionic thermal up-diffusion that promotes the selectivity and suppresses the ion-concentration polarization,especially at the low-concentration side, which results in dramatically enhanced electric power. A positive temperature difference lowers the membrane potential due to the impact of ionic thermal down-diffusion,although it promotes the diffusion current induced by decreased electrical resistance. Originating from the compromise of the temperature-impacted membrane potential and diffusion current, a positive temperature difference enhances the power at low transmembrane-concentration intensities and hinders the power for high transmembrane-concentration intensities. Based on the system’s temperature response, we have proposed a simple and efficient way to fabricate tunable ionic voltage sources and enhance salinity-gradient energy conversion based on small nanoscale biochannels and mimetic nanochannels. These findings reveal the importance of a long-overlooked element—temperature—in nanofluidic energy harvesting and provide insights for the optimization and fabrication of high-performance nanofluidic power devices.

关 键 词：energy harvesting ionic thermal up-diffusion ionic voltage source nanofluidics 

分 类 号：TB383.1[一般工业技术—材料科学与工程]