A new concept for advanced large-scale energy storage: secondary batteries with seawater as open self-replenishing cathode

世界范围内可再生能源的实施在很大程度上取决于是否有改进的技术来生产高效、安全、廉价和生态友好的固定能源储存系统。这是因为太阳能、风能和潮汐能（后者在较小程度上）等能源产生的电力是间歇性的，这意味着峰值电力输出可能与峰值需求不一致。因此，大规模的能量储存对于在需要的时间和地点不间断地提供电力供应至关重要。人们认识到，为了满足现代社会的所有需求，不同的存储技术组合是必要的，每种技术都针对给定的应用进行了优化。许多不同的电池技术，如铅酸、金属-空气、氧化还原流和锂离子电池也被提出作为存储解决方案。由于它们对环境的影响或高昂的资本和维护成本，它们都不是没有问题的。对于大规模储能来说，有效成本是由系统寿命和环境足迹决定的，这将转化为每兆瓦时的成本。在目前的“能源冒险”的框架内，我们的目标是探索一种专门针对大规模储能与海洋风能、波浪和潮汐能生产相结合的新技术。这涉及到在一个介于二次钠离子电池和燃料电池之间的混合系统中使用海水作为正极（阴极）。海水中的盐是钠离子的取之不尽的来源，钠离子在充电时通过快速离子导体膜转移到负极（阳极）。在放电过程中，钠离子从阳极回到海水中。令人兴奋和新颖的方面是，一种天然的无限资源被用作细胞的主动自我补充成分。因此，与其他相关技术相比，该系统具有许多优点：低成本、高安全性和对环境的影响可以忽略不计。该项目旨在将海水混合燃料电池从概念验证阶段发展成为大规模储能的可行技术。这将通过组件的优化、可扩展制造工艺的开发和相关环境中的验证来实现。我们的研究可以通过建立大型半水下海洋储能园区所需的技术，为储存海上产生的电力这一紧迫问题提供一种经济有效的解决方案。

World-wide implementation of renewable energy sources is substantially dependent on the availability of improved technologies for the production of efficient, safe, inexpensive and eco-friendly stationary energy storage systems. This is because the power that is produced by energy sources such as solar, wind and tidal (the latter to a smaller extent) is intermittent - implying that the peak electrical output may not coincide with peak demand. For this reason large-scale energy storage is essential to provide electrical supply when and where is needed without interruptions. It is recognized that to meet all the requirements of modern society a portfolio of different storage technology are necessary, each one optimized for a given application. Many different battery technologies such as lead acid, metal-air, redox flow and lithium-ion have also been proposed as storage solution. They are each not without their issues due to their environmental impact or for the high capital and maintenance cost. For large scale energy storage the effective cost is determined by the life-time of the system and its environmental foot print, which will be transferred to the cost per MWh. Within the framework of the present call "Adventures in Energy" we aim to explore a novel technology targeted specifically to large-scale energy storage coupled with marine wind, wave and tidal power production. This involves the use of sea-water as a positive electrode (cathode) in a hybrid system which is intermediate between a secondary sodium-ion battery and a fuel cell. The salt in sea-water is an inexhaustible source of sodium ions that are transferred to the negative electrode (anode) through a fast ionic-conductor membrane while charging. During discharge the sodium ions shuffle back from the anode to the sea-water. The exciting and novel aspect of this is that a natural unlimited resource is used as an active self-replenishing component of the cell. As a consequence the system offers numerous advantages: low cost, high safety and negligible environmental impact as compared to other related technologies. The project aims to take the sea-water hybrid fuel cell from the proof-of-concept stage to a viable technology for large scale energy storage. This will be achieved through the optimisation of constituent components, development of scalable manufacturing processes and validation in a relevant environment. Our research could provide a cost-effective solution to the pressing problem of storing electricity produced in the sea by enabling the technology necessary to build large-scale semi-submerged marine energy storage parks.