flammable organic liquid electrolytes to solid-state electrolytes not only endows all-solid-state lithium batteries (ASSLBs) with considerable improvements in battery safety, but also potentially allows the use of Li metal anode, which is regarded as the ultimate anode due to its high theoretical specific capacity (3860 mAh g -1 ) and low electrochemical potential (−3.04 V versus standard hydrogen electrode). [3][4][5][6][7] Thus, ASSLBs have been widely exploited as next-generation energy storage technologies with enhanced energy density and safety. [8] However, current ASSLBs are far from competitive with commercial LIBs in terms of battery performance and ease of manufacturing. [9,10] This is because conventional ASSLB assembly requires laborious fabrication of solid electrolyte and electrodes separately, followed by stacking each component together, which inevitably results in poor interfacial contact. [11,12] Radically different from LIBs, solid electrolyte in ASSLBs cannot spontaneously wet the electrodes as liquid electrolyte does, leading to discontinuous ion transport at the cathode/solid electrolyte interfaces and inside the porous cathode, which results in a large interfacial resistance and low active material utilization. [13] As a consequence, the mass loading of most reported ASSLBs is too low (usually <4 mg cm -2 ) to meet the requirement for practical energy-dense batteries. [14] In addition, due to unfavorable mechanical properties, typical solid electrolytes need to be fabricated to be overly thick as a way of ensuring their integrity under unavoidable stress during conventional cell assembly processes. [9,15] For instance, pure ceramic solid electrolytes are generally too brittle to be produced with a thickness less than 100 µm. [16,17] Although blending the ceramics with polymers can endow the composite solid electrolyte with good flexibility, it is still challenging to reduce the thickness to be comparable with that of separators (usually <30 µm) in current LIBs, which, as a result, considerably sacrifices the battery energy density. [15,18] Even worse, the inferior mechanical strength of solid electrolytes renders a poor Li dendrite suppression capability, resulting in poor cyclability of the battery. [19] These limitations of conventional ASSLB manufacturing impose a great penalty on the attainable energy density and cyclability of the battery.To address these issues, several strategies have been developed for ASSLBs. For instance, Hu et al. reported on a dense/ porous bilayer garnet electrolyte, where the porous layer served Current all-solid-state lithium battery (ASSLB) manufacturing typically involves laborious fabrication and assembly of individual electrodes and solid electrolyte, which inevitably result in large interfacial resistances. Moreover, due to the unfavorable mechanical strength, most solid electrolytes are fabricated to be overly thick and are incapable of retarding lithium dendrite formation. These factors limit the attainable energy density and cyclability of ASSLBs. Her...
