Search

Antimony sulfide (Sb2S3) is a promising electrode material. However, its poor electronic/ionic conductivity severely hinders its practical application. Herein, carbon‐coated Sb2S3 nanorods (Sb2S3@C) are synthesized to address this issue. The electrochemical performance of the Sb2S3@C is evaluated in all‐solid‐state lithium batteries (ASSLBs) using InLi anode and Li10Si0.3PS6.7Cl1.8 solid‐state electrolytes. The Sb2S3@C cathode delivers the 1st cycle discharge capacity of 711 mAh g‐1 and a stable cycling capacity of 431 mAh g‐1, which are much higher than the 1st cycle discharge capacity of 125 mAh g‐1 and a stable cycling capacity of 320 mAh g‐1 for the uncoated Sb2S3 cathode. In situ transmission electron microscopy reveals that the carbon coating layer acts as an electronic/ionic conductive conduit, which boosts the charge transfer in the electrode dramatically. Consequently, the Sb2S3@C electrochemistry quickly evolves from intercalation to conversion to full alloying. However, the Sb2S3 nanorods without carbon coating undergo sluggish intercalation and conversion reactions, and the alloying reaction is almost impeded, severely limiting the capacity. Therefore, the Sb2S3@C electrode is fully utilized thus delivering much higher capacity and rate performance than the non‐coated Sb2S3 electrode. These results demonstrate that Sb2S3@C is a promising high‐energy‐density cathode for ASSLBs. [ABSTRACT FROM AUTHOR]

Metals fluorides (MFs) are potential conversion cathodes to replace commercial intercalation cathodes. However, the application of MFs is impeded by their poor electronic/ionic conductivity and severe decomposition of electrolyte. Here, a composite cathode of FeF2 and polymer‐derived carbon (FeF2@PDC) with excellent cycling performance is reported. The composite cathode is composed of nanorod‐shaped FeF2 embedded in PDC matrix with excellent mechanical strength and electronic/ionic conductivity. The FeF2@PDC enables a reversible capacity of 500 mAh g–1 with a record long cycle lifetime of 1900 cycles. Remarkably, the FeF2@PDC can be cycled at a record rate of 60 C with a reversible capacity of 107 mAh g–1 after 500 cycles. Advanced electron microscopy reveals that the in situ formation of stable Fe3O4 layers on the surface of FeF2 prevents the electrolyte decomposition and leaching of iron (Fe), thus enhancing the cyclability. The results provide a new understanding to FeF2 electrochemistry, and a strategy to radically improve the electrochemical performance of FeF2 cathode for lithium‐ion battery applications. [ABSTRACT FROM AUTHOR]