Zhai Haowei, Gong Tianyao, Xu Bingqing, Cheng Qian, Paley Daniel, Qie Boyu, Jin Tianwei, Fu Zhenxuan, Tan Laiyuan, Lin Yuan-Hua, Nan Ce-Wen, Yang Yuan
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , P. R. China.
ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28774-28780. doi: 10.1021/acsami.9b04932. Epub 2019 Jul 30.
Safety is critical to developing next-generation batteries with high-energy density. Polyether-based electrolytes, such as poly(ethylene oxide) and poly(ethylene glycol) (PEG), are attractive alternatives to the current flammable liquid organic electrolyte, since they are much more thermally stable and compatible with high-capacity lithium anode. Unfortunately, they are not stable with 4 V Li(NiMnCo)O (NMC) cathodes, hindering them from application in batteries with high-energy density. Here, we report that the compatibility between PEG electrolyte and NMC cathodes can be significantly improved by forming a 2 nm AlO coating on the NMC surface. This nanoscale coating dramatically changes the composition of the cathode electrolyte interphase and thus stabilizes the PEG electrolyte with the NMC cathode. With AlO, the capacity remains at 84.7% after 80 cycles and 70.3% after 180 cycles. In contrast, the capacity fades to less than 50% after only 20 cycles in bare NMC electrodes. This study opens a new opportunity to develop safe electrolyte for lithium batteries with high-energy density.
安全性对于开发高能量密度的下一代电池至关重要。基于聚醚的电解质，如聚环氧乙烷和聚乙二醇（PEG），是当前易燃液体有机电解质颇具吸引力的替代品，因为它们的热稳定性更高，且与高容量锂负极兼容。不幸的是，它们与4V的锂镍锰钴氧化物（NMC）正极不稳定，这阻碍了它们在高能量密度电池中的应用。在此，我们报告通过在NMC表面形成2nm的AlO涂层，可以显著提高PEG电解质与NMC正极之间的兼容性。这种纳米级涂层极大地改变了正极电解质界面的组成，从而使PEG电解质与NMC正极稳定。使用AlO时，80次循环后容量保持在84.7%，180次循环后保持在70.3%。相比之下，在裸露的NMC电极中，仅20次循环后容量就降至50%以下。这项研究为开发用于高能量密度锂电池的安全电解质开辟了新机会。
