Abstract Oxide-based all-solid-state lithium-ion battery is prepared by a conventional sintering process, thanks to the intrinsic low melting point of Li2.2C0.8B0.2O3. A well-defined interface between LiCoO2 and Li2.2C0.8B0.2O3 was confirmed without any traces of impurities. Li ion reversibly (de-)intercalated from/into LiCoO2 at initial charge–discharge process when the charge capacity was limited to 120 mAh g− 1. The capacity degradation after subsequent cycling was suppressed by further limitation of the charging capacity. However, capacity fade could still be confirmed after 20 cycles albeit the capacity was limited at 60 mAh g− 1. This study suggests large repetitive expansion–contraction of the electrode during cycling as a possible cause of fatigue failure of the electrode/oxide electrolyte interface.