Suppressing Ionic-to-Electronic Conduction Transition on Cathode Interface Enables 4.4 V Poly(ethylene oxide)-Based All-Solid-State Batteries

作者：Zi-Xiang Kong, Zhe Xiong, Jian‐Fang Wu, Jun Jin, Yuxiao Lin, Yunsong Li, Jilei Liu · 发表于：ACS Energy Letters · 年份：2024 · DOI：10.1021/acsenergylett.4c02840 · 被引用次数：27 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced Battery Technologies Research

The implementation of energy-dense poly(ethylene oxide) (PEO)-based all-solid-state lithium batteries is impeded by the limited working voltage and underexplored cathode interfacial reaction mechanism. Here, through analyzing interfacial resistances using the Wagner model, the change of the interfacial reaction parameter ( k ) is proposed to unveil the ionic-to-electronic conduction transition and kinetic formation mechanism of the cathode-electrolyte-interphase (CEI) under voltage ≥4.2 V, thereby constructing ionic conductor-dominated CEIs to enable 4.4 V batteries. With the open-circuit voltage ≥4.2 V, k 1 and k 2 are derived; k 2 is smaller than k 1, caused by the enhanced electronic conduction and indicating the ionic-to-electronic conduction transition of the CEI. Moreover, by introducing LiPO 2 F 2 in high-concentration solid electrolytes, ionic conductors Li 3 PO 4 and Li x POF y dominate the CEI, overcoming the ionic-to-electronic conduction transition; the resulting 4.4 V cell bears a discharge capacity of 130 mAh/g with a retention of 90% after 100 cycles, about 2 times that of the normal PEO-based cell.