Challenges posed by the intermittency of solar energy source necessitate the integration of solar energy conversion with scalable energy storage systems. The monolithic integration of photoelectrochemical solar energy conversion and electrochemical energy storage offers an efficient and compact approach toward practical solar energy utilization. Here, we present the design principles for and the demonstration of a highly efficient integrated solar flow battery (SFB) device with a record solar-to-output electricity efficiency of 14.1%. Such SFB devices can be configured to perform all the requisite functions from solar energy harvest to electricity redelivery without external bias. Capitalizing on high-efficiency and high-photovoltage tandem III-V photoelectrodes that are properly matched with high-cell-voltage redox flow batteries and carefully designed flow field architecture, we reveal the general design principles for efficient SFBs. These results will enable a highly efficient approach for practical off-grid solar utilization and electrification.

太阳能源间断性带来的挑战需要将太阳能转换与可扩展的储能系统集成在一起。光电化学太阳能转换和电化学能量存储的单片集成为实际的太阳能利用提供了一种高效而紧凑的方法。在这里，我们介绍了高效集成太阳能流电池（SFB）设备的设计原理和演示，其太阳能到输出的电效率达到了创纪录的14.1％。这样的SFB设备可以配置为执行所有必要的功能，从太阳能收集到重新交付电力，而无需外部偏置。利用与高电池电压氧化还原液流电池正确匹配的高效，高光电压串联III-V光电电极以及精心设计的流场架构，我们揭示了高效SFB的一般设计原理。这些结果将为实际的离网太阳能利用和电气化提供一种高效的方法。