ABSTRACT
Li6.3La3Zr1.65W0.35O12 (LLZO)-Li6PS5Cl (LPSC) composite electrolytes and all-solid-state cells containing LLZO-LPSC were fabricated by cold pressing at room temperature. The LPSC:LLZO ratio was varied, and the microstructure, ionic conductivity, and electrochemical performance of the corresponding composite electrolytes were investigated; the ionic conductivity of the composite electrolytes was three or four orders of magnitude higher than that of LLZO. The high conductivity of the composite electrolytes was attributed to the enhanced relative density and the rule of mixture for soft LPSC particles with high lithium-ion conductivity (~10-4 S·cm-1). The specific capacities of all-solid-state cells (ASSCs) consisting of a LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and the composite electrolytes of LLZO:LPSC = 7:3 and 6:4 were 163 and 167 mAh·g-1, respectively, at 0.1 C and room temperature. Moreover, the charge-discharge curves of the ASSCs with the composite electrolytes revealed that a good interfacial contact was successfully formed between the NCM811 cathode and the LLZO-LPSC composite electrolyte.
ABSTRACT
Lithium argyrodite Li6PS5Cl powders are synthesized from Li2S, P2S5, and LiCl via wet milling and post-annealing at 500°C for 4 h. Organic solvents such as hexane, heptane, toluene, and xylene are used during the wet milling process. The phase evolution, powder morphology, and electrochemical properties of the wet-milled Li6PS5Cl powders and electrolytes are studied. Compared to dry milling, the processing time is significantly reduced via wet milling. The nature of the solvent does not affect the ionic conductivity significantly; however, the electronic conductivity changes noticeably. The study indicates that xylene and toluene can be used for the wet milling to synthesize Li6PS5Cl electrolyte powder with low electronic and comparable ionic conductivities. The all-solid-state cell with the xylene-processed Li6PS5Cl electrolyte exhibits the highest discharge capacity of 192.4 mAh·g-1 and a Coulombic efficiency of 81.3% for the first discharge cycle.
ABSTRACT
A lithium-oxygen battery based on a triplex-Li+-selective solid membrane (LSSM) is proposed. An inorganic LSSM with a triplex (porous/dense/porous) structure is prepared via tape-casting. The cell exhibits promising rate-capability and reversibility during cycling. The triplex-LSSM architecture may allow cell designs to be scaled up for use in large systems.
