Solid-state lithium-ion batteries for grid energy storage: opportunities and challenges

The energy crisis and environmental pollution drive more attention to the development and utilization of renewable energy. Considering the capricious nature of renewable energy resource, it has difficulty supplying electricity directly to consumers stably and efficiently, which calls for energy storage systems to collect energy and release electricity at peak periods. Due to their flexible power and energy, quick response, and high energy conversion efficiency, lithium-ion batteries stand out among multiple energy storage technologies and are rapidly deployed in the grid. Pursuing superior performance and ensuring the safety of energy storage systems, intrinsically safe solid-state electrolytes are expected as an ideal alternative to liquid electrolytes. In this review, we systematically evaluate the priorities and issues of traditional lithium-ion batteries in grid energy storage. Beyond lithium-ion batteries containing liquid electrolytes, solid-state lithium-ion batteries have the potential to play a more significant role in grid energy storage. The challenges of developing solid-state lithium-ion batteries, such as low ionic conductivity of the electrolyte, unstable electrode/electrolyte interface, and complicated fabrication process, are discussed in detail. Additionally, the safety of solid-state lithium-ion batteries is re-examined. Following the obtained insights, inspiring prospects for solid-state lithium-ion batteries in grid energy storage are depicted. [Figure not available: see fulltext.]