Abstract：
The cathode surface of sulfide-based all-solid-state batteries (SBs) is commonly coated with amorphous-LiNbO3 in order to stabilize charge-discharge reactions. However, high-voltage charging diminishes the advantages, which is caused by problems with the amorphous-LiNbO3 coating layer. This study has investigated the degradation of amorphous-LiNbO3 coating layer directly during the high-voltage charging of SBs. O2 generation via Li extraction from the amorphous-LiNbO3 coating layer is observed using electrochemical gas analysis and electrochemical X-ray photoelectron spectroscopy. This O2 leads to the formation of an oxidative solid electrolyte (SE) around the coating layer and degrades the battery performance. On the other hand, elemental substitution (i.e., amorphous-LiNbxP1- xO3) reduces O2 release, leading to stable high-voltage charge-discharge reactions of SBs. The results have emphasized that the suppression of O2 generation is a key factor in improving the energy density of SBs.
摘要：
基于硫化物的全固态电池（SB）的阴极表面通常涂有无定形LiNbO3，以稳定充放电反应。然而,高压充电削弱了优势，这是由非晶LiNbO3涂层的问题引起的。这项研究直接研究了在SBs的高压充电过程中非晶LiNbO3涂层的降解。使用电化学气体分析和电化学X射线光电子能谱观察到通过从无定形LiNbO3涂层中提取Li而产生的O2。该O2导致在涂层周围形成氧化固体电解质(SE)并降低电池性能。另一方面,元素取代(即，无定形-LiNbxP1-xO3)减少O2释放，导致SB稳定的高压充放电反应。结果强调，抑制O2的产生是提高SB能量密度的关键因素。
