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Chalcogenide solid-state electrolytes (SEs) have been regarded as promising candidates for lithium dendrite suppression due to their high ionic conductivity, suitable mechanical strength, and large Li+ion transference number. However, the wide applications of SEs in pragmatic all-solid-state batteries are still retarded by their limited interface stability, which leads to lithium dendrite growth and formation of interphase with high resistance. In addition, the interphase evolution mechanism between SEs and metallic Li anodes remains unclear. Herein, this work demonstrates that the interfacial stability of Li2S–SiS2–P2S5SEs can be effectively enhanced by tuning the interphase through LiI incorporation. This strategy contributes to a high ionic conductivity of the SEs and electronic insulation interphase containing LiI. Thus, the 70(60Li2S–28SiS2–12P2S5)–30 LiI SEs prepared by melt-quenching exhibit a high ionic conductivity of 1.74 mS cm–1at room temperature and a larger critical current density of 1.65 mA cm–2at 65 °C. The cycling life of the symmetric Li|SEs|Li cell is up to 200 h without significant resistance growth at 0.1 mA cm–2at room temperature. This enhanced interface stability is revealed to originate from the in situ-formed LiI within the interphase, which prevents continual SEs degradation and suppresses lithium dendrite growth. This work provides a vital understanding of interphase evolution, which is valuable for designing SEs with long cycling stability.

Wearable thermal sensors based on thermoelectric (TE) materials with high sensitivity and temperature resolution are extensively used in medical diagnosis, human–machine interfaces, and advanced artificial intelligence. However, their development is greatly limited by the lack of materials with both a high Seebeck coefficient and superior anticrystallization ability. Here, a new inorganic amorphous TE material, Ge15Ga10Te75, with a high Seebeck coefficient of 1109 μV/K is reported. Owing to the large difference between the glass-transition temperature and initial crystallization temperature, Ge15Ga10Te75strongly inhibits crystallization during fiber fabrication by thermally codrawing a precast rod comprising a Ge15Ga10Te75core and PP polymer cladding. The temperature difference can be effectively transduced into electrical signals to achieve TE fiber thermal sensing with an accurate temperature resolution of 0.03 K and a fast response time of 4 s. It is important to note that after the 1.5 and 5.5 K temperatures changed repeatedly, the TE properties of the fiber demonstrated high stability. Based on the Seebeck effect and superior flexibility of the fibers, they can be integrated into a mask and wearable fabric for human respiration and body temperature monitoring. The superior thermal sensing performance of the TE fibers together with their natural flexibility and scalable fabrication endow them with promising applications in health-monitoring and intelligent medical systems.