Solid state lithium secondary batteries using an amorphous solid electrolyte in the system (100-x)(0.6Li(2)S center dot 0.4SiS(2)) center dot xLi(4)SiO(4) obtained by mechanochemical synthesis

Electrochemical cells were constructed using amorphous materials in the sys tem (100 - x)(0.6Li(2)S .0.4SiS(2)). xLi(4)SiO(4), obtained by mechanochemi cal synthesis, as an electrolyte, LiCoO2 as a positive electrode and indium as a negative electrode. Charge and discharge behaviors of the cells at a constant current were investigated to see the possibility for utilization a s secondary batteries. Charge-discharge efficiency at the Ist cycle was mor e than 75% in the cells using the solid electrolytes synthesized by mechani cal milling (MM) for more than 5 h. Charge-discharge curves of the cells us ing the amorphous materials milled fur more than 10 h, were similar to thos e of the cells using the corresponding melt-quenched glass samples. The cha rge-discharge capacity decreased gradually from 90 to 70 mA h/g till about the 10th cycle, and became stable after the 10th cycle. The Coulombic effic iency of the cell showed almost 100%, except for the Ist and 2nd cycles. Th e amorphous materials synthesized by MM were concluded to work as the elect rolyte for solid state lithium secondary batteries, (C) 2001 Elsevier Scien ce B.V. All rights reserved.