废水可能看上去不像可充电电池的能量来源，但是Yi Cui及其同事制造出了一种混合电池，在这种电池中，微生物把废水中的有机物质转化成电力。这种电通过一个外部电路可供使用，然后回到了这个电池内部的一个固态电极。当这个电极失效之后，可以把它取出并通过接触氧而恢复。重新装上这个电极就能恢复供能。这组作者报告说，这种电池通过阻止这些微生物暴露在氧中从而实现了高效能量捕获，而它的单室设计和没有离子交换膜提升了效率。这组作者报告说净效率大约是30%，相当于商品化太阳能电池。在理论上，生活废水中的有机物可以被氧化从而产生处理废水所需的能量的3倍；目前，发达国家使用它们的电力的3%用于这类水处理。尽管这组作者警告说在这种装置变得适合大规模电力生产之前需要找到低成本的材料，这组作者说这些发现表明了微生物电池的概念可以有效地把废水转化成可用能量。（生物谷 Bioon.com）
生物谷推荐的英文摘要
PNAS doi: 10.1073/pnas.1307327110
Microbial battery for efficient energy recovery
Xing Xiea,b, Meng Yea, Po-Chun Hsub, Nian Liuc, Craig S. Criddlea,1, and Yi Cuib,d,1
By harnessing the oxidative power of microorganisms, energy can be recovered from reservoirs of less-concentrated organic matter, such as marine sediment, wastewater, and waste biomass. Left unmanaged, these reservoirs can become eutrophic dead zones and sites of greenhouse gas generation. Here, we introduce a unique means of energy recovery from these reservoirs—a microbial battery (MB) consisting of an anode colonized by microorganisms and a reoxidizable solid-state cathode. The MB has a single-chamber configuration and does not contain ion-exchange membranes. Bench-scale MB prototypes were constructed from commercially available materials using glucose or domestic wastewater as electron donor and silver oxide as a coupled solid-state oxidant electrode. The MB achieved an efficiency of electrical energy conversion of 49% based on the combustion enthalpy of the organic matter consumed or 44% based on the organic matter added. Electrochemical reoxidation of the solid-state electrode decreased net efficiency to about 30%. This net efficiency of energy recovery (unoptimized) is comparable to methane fermentation with combined heat and power.
