Liu Qian, Rao Apparao M, Han Xu, Lu Bingan
State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle Engineering Hunan University Changsha 410082 China.
Department of Physics and Astronomy Clemson Nanomaterials Institute Clemson University Clemson SC 29634 USA.
Adv Sci (Weinh). 2021 Feb 8;8(9):2003639. doi: 10.1002/advs.202003639. eCollection 2021 May.
Although graphite with its merits of low cost, abundance, and environmental friendliness is a potential anode material for potassium ion batteries (PIBs), it suffers from a limited cycle life due to a severe decomposition of the solid electrolyte interface (SEI) in organic electrolytes. Herein, a simple and viable method is demonstrated for the first time through which an ultra-thin, uniform, dense, and stable artificial inorganic SEI film can be prepared on commercial graphite anodes and used with traditional carbonate electrolytes to achieve PIBs with long-cycle stability and high initial Coulombic efficiency (ICE). Specifically, such commercial graphite anodes exhibit a long-term cycling stability for more than 1000 cycles at 100 mA g (a reversible capacity of around 260 mAh g) and a high average CE (around 99.9%) in traditional carbonate electrolytes with no discernable decay in capacity. More importantly, the commercial graphite anodes with the artificial inorganic SEI film in traditional carbonate electrolytes can deliver a high ICE of 93% (the highest ICE ever reported for PIBs anodes until now), which improves the performance of the PIB full cell. Considering the high ICE and long cycle stability performance, this study can promote the rapid deployment of PIBs on a commercial scale.
尽管石墨具有低成本、储量丰富和环境友好等优点，是钾离子电池（PIB）的潜在负极材料，但由于其在有机电解质中固体电解质界面（SEI）的严重分解，导致其循环寿命有限。在此，首次展示了一种简单可行的方法，通过该方法可以在商用石墨负极上制备超薄、均匀、致密且稳定的人工无机SEI膜，并与传统碳酸盐电解质一起使用，以实现具有长循环稳定性和高初始库仑效率（ICE）的PIB。具体而言，这种商用石墨负极在100 mA g（可逆容量约为260 mAh g）下在传统碳酸盐电解质中表现出超过1000次循环的长期循环稳定性，且平均CE较高（约99.9%），容量无明显衰减。更重要的是，在传统碳酸盐电解质中带有人工无机SEI膜的商用石墨负极可提供93%的高ICE（这是迄今为止报道的PIB负极中最高的ICE），这提高了PIB全电池的性能。考虑到高ICE和长循环稳定性性能，本研究可推动PIB在商业规模上的快速应用。
