The implementation of inexpensive and reliable energy storage technologies is crucial for the decarbonisation of energy intensive industry branches and energy supply. Sensible thermal energy storage (TES) in molten salts is a key technology for storage of heat in the scale of gigawatt hours but currently limited to operating temperatures of 560 °C. Increasing the maximum operating temperature while maintaining thermal stability of the storage medium is one of the main challenges next-Generation TES systems are facing. Extending the upper temperature limit by only 40 °C increases the storage capacity by more than 16% allowing for more compact storage designs and cost savings in the $ million-range for large scale storage units. Here we propose a novel storage technology from a materials point of view that pushes the thermal stability limit of Solar Salt up to 600 °C by simply but effectively sealing the storage unit including the gas system. The concentration of the unstable nitrite ion and of the corrosive oxide ion could be reduced by 16% and 75%, respectively at 600 °C, compared to a salt system with open atmosphere. We present clear evidence of the enhanced thermal stability in long-term, 100 g-scale test campaigns at previously unequalled temperatures. These findings constitute a major advance in the design and engineering of next generation storage systems.

廉价可靠的储能技术的实施对于能源密集型行业分支和能源供应的脱碳至关重要。熔融盐中的显热能存储（TES）是用于以千兆瓦时规模存储热量的一项关键技术，但目前仅限于560°C的工作温度。在保持存储介质的热稳定性的同时提高最高工作温度是下一代TES系统面临的主要挑战之一。仅将温度上限提高40°C，存储容量就会增加16％以上，从而可以实现更紧凑的存储设计，并为大型存储单元节省了数百万美元的成本。在这里，我们从材料的角度提出一种新颖的存储技术，该方法通过简单而有效地密封包括气体系统的存储单元，将太阳能盐的热稳定性极限提高到600°C。与具有开放气氛的盐体系相比，在600°C下，不稳定的亚硝酸盐离子和腐蚀性氧化物离子的浓度分别降低了16％和75％。我们提供了在以前无与伦比的温度下长期100 g规模测试活动中增强的热稳定性的明确证据。这些发现构成了下一代存储系统设计和工程的重大进步。与开放气氛的盐体系相比，温度分别为600°C。我们提供了在以前无与伦比的温度下长期100 g规模测试活动中增强的热稳定性的明确证据。这些发现构成了下一代存储系统设计和工程的重大进步。与开放气氛的盐体系相比，温度分别为600°C。我们提供了在以前无与伦比的温度下长期100 g规模测试活动中增强的热稳定性的明确证据。这些发现构成了下一代存储系统设计和工程的重大进步。