新型全液态铁液流电池用于电网储能

A commonplace chemical used in water treatment facilities has been repurposed for large-scale energy storage in a new battery design by researchers at the Department of Energy's Pacific Northwest National Laboratory. The design provides a pathway to a safe, economical, water-based, flow battery made with Earth-abundant materials. It provides another pathway in the quest to incorporate intermittent energy sources such as wind and solar energy into the nation's electric grid.
美国能源部西北太平洋国家实验室的研究人员将一种水处理设施常用的普通化学品重新用于新型电池设计，实现了大规模储能。该设计为利用地球富产材料制造安全、经济、水基液流电池提供了可行路径，为将风能和太阳能等间歇性能源纳入国家电网的探索开辟了另一条途径。

The researchers report in Nature Communications that their lab-scale, iron-based battery exhibited remarkable cycling stability over one thousand consecutive charging cycles, while maintaining 98.7 percent of its maximum capacity. For comparison, previous studies of similar iron-based batteries reported degradation of the charge capacity two orders of magnitude higher, over fewer charging cycles.
研究人员在《自然-通讯》上报告称，他们实验室规模的铁基电池在连续一千次充放电循环中表现出卓越的循环稳定性，同时保持了98.7%的最大容量。作为对比，此前对类似铁基电池的研究报告显示，在更少的充放电循环中，电荷容量退化程度高出两个数量级。

Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available. What makes this battery different is that it stores energy in a unique liquid chemical formula that combines charged iron with a neutral-pH phosphate-based liquid electrolyte, or energy carrier. Crucially, the chemical, called nitrogenous triphosphonate, nitrilotri-methylphosphonic acid or NTMPA, is commercially available in industrial quantities because it is typically used to inhibit corrosion in water treatment plants.
专为大规模储能设计的铁基液流电池自20世纪80年代就已问世，部分型号现已实现商业化。该电池的独特之处在于其采用了一种结合带电铁元素与中性pH磷酸盐基液态电解质（即能量载体）的特殊液体化学配方来储存能量。关键在于这种名为含氮三膦酸酯（nitrilotri-methylphosphonic acid，简称NTMPA）的化合物已在工业规模实现商用，因其常用作水处理厂的缓蚀剂。

Phosphonates, including NTMPA, are a broad chemical family based on the element phosphorus. Many phosphonates dissolve well in water and are nontoxic chemicals used in fertilizers and detergents, among other uses.
膦酸盐（包括NTMPA）是一个基于磷元素的广泛化学家族。许多膦酸盐易溶于水，是无毒化学品，可用于肥料和洗涤剂等多种用途。

"We were looking for an electrolyte that could bind and store charged iron in a liquid complex at room temperature and mild operating conditions with neutral pH," said senior author Guosheng Li, a senior scientist at PNNL who leads materials development for rechargeable energy storage devices. "We are motivated to develop battery materials that are Earth-abundant and can be sourced domestically."
“我们正在寻找一种电解质，它能在室温、中性pH值和温和操作条件下，将带电铁结合并储存在液态复合物中，”资深作者、PNNL负责可充电储能设备材料开发的高级科学家Guosheng Li表示。“我们的动机是开发地球上储量丰富且可在国内获取的电池材料。”

What is a flow battery?
什么是液流电池？

As their name suggests, flow batteries consist of two chambers, each filled with a different liquid. The batteries charge through an electrochemical reaction and store energy in chemical bonds. When connected to an external circuit, they release that energy, which can power electrical devices. Unlike other conventional batteries, flow batteries feature two external supply tanks of liquid constantly circulating through them to supply the electrolyte, serving as the battery system's "blood supply." The larger the electrolyte supply tank, the more energy the flow battery can store.
顾名思义，液流电池由两个腔室组成，每个腔室充满不同的液体。电池通过电化学反应充电，并将能量储存在化学键中。当连接到外部电路时，它们会释放能量，为电子设备供电。与其他传统电池不同，液流电池具有两个外部液体供应罐，液体不断循环以提供电解质，作为电池系统的"blood supply"。电解质供应罐越大，液流电池能储存的能量就越多。

Flow batteries can serve as backup generators for the electric grid. Flow batteries are one of the key pillars of a decarbonization strategy to store energy from renewable energy resources. Their advantage is that they can be built at any scale, from the lab-bench scale, as in the PNNL study, to the size of a city block.
液流电池可以作为电网的备用发电机。液流电池是存储可再生能源以实现去碳化策略的关键支柱之一。它们的优势在于可以构建任何规模，从实验室规模（如PNNL研究中的规模）到城市区块的大小。

In the near term, grid operators are looking to locate battery energy storage systems (BESS) in urban or suburban areas near energy consumers. Often, city planners must grapple with consumer safety concerns. The type of aqueous flow battery reported here could help alleviate safety concerns.
近期，电网运营商正寻求在能源消费者附近的城区或郊区部署电池储能系统（BESS）。城市规划者常常需要应对消费者对安全性的担忧。本文报道的这种水系液流电池（aqueous flow battery）或有助于缓解安全性问题。

"A BESS facility using the chemistry similar to what we have developed here would have the advantage of operating in water at neutral pH," said Aaron Hollas, a study author and team leader in PNNL's Battery Materials and Systems Group. "In addition, our system uses commercially available reagents that haven't been previously investigated for use in flow batteries."
“使用与我们在此开发的化学性质相似的BESS设施将具有在中性pH值的水中运行的优势，”研究作者、PNNL电池材料与系统小组的团队负责人Aaron Hollas表示，“此外，我们的系统使用了市售试剂，这些试剂以前未被研究用于液流电池。”

The research team reported that their initial design can reach energy density, a key design feature, up to 9 watt-hours per liter (Wh/L). In comparison, commercialized vanadium-based systems are more than twice as energy dense, at 25 Wh/L. Higher energy density batteries can store more energy in a smaller square footage, but a system built with Earth-abundant materials could be scaled to provide the same energy output.
研究团队报告称，其初始设计可实现高达9瓦时每升（Wh/L）的能量密度，这是一项关键设计特征。相比之下，已商业化的钒基系统能量密度达25 Wh/L，是其两倍多。更高能量密度的电池能在更小体积中存储更多能量，而采用地球富产材料构建的系统可通过扩大规模实现同等能量输出。

Future development of aqueous redox flow batteries
水系氧化还原液流电池的未来发展

"Our next step is to improve battery performance by focusing on aspects such as voltage output and electrolyte concentration, which will help to increase the energy density," said Li. "Our voltage output is lower than the typical vanadium flow battery output. We are working on ways to improve that."
李表示："我们的下一步是通过聚焦电压输出和电解液浓度等方面来提升电池性能，这将有助于提高能量密度。目前我们的电压输出低于典型全钒液流电池水平，我们正在研究改进方案。"

PNNL researchers plan to scale-up this and other new battery technologies at a new facility called the Grid Storage Launchpad (GSL) opening at PNNL in 2024. The GSL, funded by the Department of Energy's Office of Electricity, which also funded the current study, will help accelerate the development of future flow battery technology and strategies so that new energy storage systems can be deployed safely.
PNNL的研究人员计划在2024年启用的新设施Grid Storage Launchpad（GSL）中扩大这种电池技术及其他新型电池技术的规模。GSL由美国能源部电力办公室资助（该机构也资助了当前研究），将助力加速未来液流电池技术和策略的开发，从而安全部署新型储能系统。

Study contributors included co-lead authors Gabriel S. Nambafu and Hollas, as well as Peter S. Rice, Daria Boglaienko, John L. Fulton, Miller Li, Qian Huang, David M. Reed, Vincent L. Sprenkle, and G. Li from PNNL. Shuyuan Zhang and Yu Zhu from the University of Akron in Akron, Ohio, also participated in the research.
研究参与者包括共同第一作者Gabriel S. Nambafu和Hollas，以及来自PNNL的Peter S. Rice、Daria Boglaienko、John L. Fulton、Miller Li、Qian Huang、David M. Reed、Vincent L. Sprenkle和G. Li。来自俄亥俄州阿克伦市阿克伦大学的Shuyuan Zhang和Yu Zhu也参与了这项研究。