▲ 作者:Huimin Song, Konrad Münch, Xu Liu, Kaier Shen, Ruizhuo Zhang, Timo Weintraut, et al.
▲ 链接:
https://www.nature.com/articles/s41586-024-08298-9
▲ 摘要:
全固态锂硫电池(ASSLSB)具有高比能、高安全性和低成本的优点,是下一代储能的理想选择。然而,因三相边界处缓慢的固-固硫氧化还原反应(SSSRR)导致的速率性能差和循环寿命短的问题仍有待解决。
研究组展示了一种由硫代磷酸碘化锂(LBPSI)玻璃相固体电解质(GSEs)实现的快速SSSRR。基于I−和I2/I3−之间的可逆氧化还原,固体电解质(SE)不仅作为超离子导体,还可作为表面氧化还原介质,促进了固-固两相边界处的缓慢反应,从而大大增加了活性位点的密度。
通过这种机制,ASSLSB表现出超快充电能力,在2C(30°C)充电时显示出1497 mAh g−1硫的高比容量,而在20C时仍保持784 mAh g−1硫。值得注意的是,在60°C下以150 C的极限速率充电时,仍可实现432 mAh g−1硫的比容量。
此外,该电池在5C(25°C)下具有超过25000次循环的优异循环稳定性,容量保持率为80.2%。研究组希冀这项氧化还原介导SSSRR的工作将为开发高能量且安全的先进ASSLSBs铺平道路。
▲ Abstract:
With promises for high specific energy, high safety and low cost, the all-solid-state lithium–sulfur battery (ASSLSB) is ideal for next-generation energy storage. However, the poor rate performance and short cycle life caused by the sluggish solid–solid sulfur redox reaction (SSSRR) at the three-phase boundaries remain to be solved. Here we demonstrate a fast SSSRR enabled by lithium thioborophosphate iodide (LBPSI) glass-phase solid electrolytes (GSEs). On the basis of the reversible redox between I− andI2/I3−, the solid electrolyte (SE)—as well as serving as a superionic conductor—functions as a surficial redox mediator that facilitates the sluggish reactions at the solid–solid two-phase boundaries, thereby substantially increasing the density of active sites. Through this mechanism, the ASSLSB exhibits ultrafast charging capability, showing a high specific capacity of 1,497 mAhg−1sulfur on charging at 2C (30°C), while still maintaining 784mAh g−1sulfur at 20C. Notably, a specific capacity of 432 mAh g−1sulfur is achieved on charging at an extreme rate of 150C at 60°C. Furthermore, the cell demonstrates superior cycling stability over 25,000 cycles with 80.2% capacity retention at 5C (25°C). We expect that our work on redox-mediated SSSRR will pave the way for developing advanced ASSLSBs that are high energy and safe.