Single-step prepared Li2S-P2S5-C composite cathode for high areal capacity all-solid-state lithium ion batteries

•Li2S-P2S5-C composite cathode was prepared by single-step process.•ASSBs with the composite cathode were fabricated and tested.•The single-step method improved the morphology and three- phase distribution.•Gravimetric capacities were enhanced with the single-step cathode.•The single step method was effective for achieving high areal capacities. All-solid-state-batteries (ASSBs) consisting of a Li2S-P2S5-C composite cathode, sulfide-based glass (Li2S∙P2S5) and an In anode are prepared via a single-step cathode preparation method. The great advantage of the single-step preparation is that the solid electrolyte synthesis process is carried out simultaneously with the process for preparing the composite cathode. This improves the cathode morphology and the three- phase distribution and saves preparation time. The results of impedance spectroscopy and the galvanostatic intermittent titration technique indicate that making ASSBs with the single-step cathode brings about a much lower charge transfer and interfacial resistance compared to that with the two-step cathode, which is due to the improved electrode microstructure. Consequently, an ASSB with a single-step cathode demonstrates higher charge-discharge capacities. Moreover, much higher (~8 times higher) areal capacities are achieved in comparison with the reported values while the reasonable gravimetric capacities are maintained. Thus, it can be said that the single-step preparation method is effective for achieving high area capacity in all-solid-state Li2S-P2S5 batteries.