[论文解读] Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment

Zihan Xu, Guòan Tai+3 more|arXiv (Cornell University)|Mar 1, 2012

Graphene research and applications参考文献 12被引用 5

一句话总结

本文提出一种基于石墨烯的自充电电池，通过非对称电极结构将水溶液中离子运动的环境热能转化为电能。该电池在饱和CuCl₂溶液中可稳定输出0.35 V电压，持续时间超过20天，且电压随温度和阳离子浓度升高而增加，证明了在便携式和自供电设备中利用环境热能的可行性。

ABSTRACT

The energy of ionic thermal motion presents universally, which is as high as 4 kJ\bullet kg-1\bullet K-1 in aqueous solution, where thermal velocity of ions is in the order of hundreds of meters per second at room temperature1,2. Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric electrodes configuration to capture such ionic thermal energy and convert it into electricity. An output voltage around 0.35 V was generated when the device was dipped into saturated CuCl2 solution, in which this value lasted over twenty days. A positive correlation between the open-circuit voltage and the temperature, as well as the cation concentration, was observed. Furthermore, we demonstrated that this finding is of practical value by lighting a commercial light-emitting diode up with six of such graphene devices connected in series. This finding provides a new way to understand the behavior of graphene at molecular scale and represents a huge breakthrough for the research of self-powered technology. Moreover, the finding will benefit quite a few applications, such as artificial organs, clean renewable energy and portable electronics.

研究动机与目标

• 开发一种无需外部输入即可将环境热能转化为电能的自供电能量采集装置。
• 探索利用水溶液中离子热运动作为可再生能源的可行性。
• 展示一种基于石墨烯的装置，仅依靠环境热能即可实现持续电压输出。
• 建立一种适用于便携式和生物医学应用的可扩展、低成本能量采集方法。

提出的方法

• 该装置采用石墨烯作为电极，通过非对称电极结构捕获电解质溶液中的离子热运动。
• 电极浸入饱和CuCl₂溶液中，以促进离子与电极的相互作用及电荷分离。
• 电压的产生源于离子热运动撞击石墨烯电极，从而诱导出净电势差。
• 系统在20天内保持稳定的开路电压，表明其长期运行稳定性。
• 将多个装置串联（六个单元）连接以驱动商用LED，验证了其实际功能。
• 理论分析表明电压输出与温度和阳离子浓度正相关。

实验结果

研究问题

• RQ1 能否高效地从水溶液中的离子热运动中采集电能？
• RQ2 基于石墨烯的装置利用环境热能可实现的最大稳定电压输出是多少？
• RQ3 温度和阳离子浓度如何影响该系统中的电压输出？
• RQ4 该装置能否在无外部能量输入的情况下长期维持电能生成？
• RQ5 所采集的能量是否足以驱动如LED等实际电子元件？

主要发现

• 当装置浸入饱和CuCl₂溶液中超过20天时，产生了约0.35 V的稳定开路电压。
• 开路电压与电解质中的温度和阳离子浓度均呈正相关。
• 六个此类装置串联后成功点亮了商用发光二极管，证明了其实际能量输出能力。
• 该系统利用了来自离子运动的环境热能，而这种能量由环境持续补充。
• 电压输出在长时间内保持一致，表明基于石墨烯的能量采集器具有优异的鲁棒性和长期稳定性。
• 研究结果表明，该方法为利用石墨烯和环境热能实现自供电设备提供了一条可扩展的路径。