$CO_{2}$ Gas Sensing Characteristics of Lithium ionic Solid Electrolyte prepared by Sol-gel Method

Sol-gel법에 의한 Li 이온-고체 전해질의 $CO_{2}$ 가스 감지 특성

Lithium ionic solid electrolyte was synthesized at $60^{\circ}C$ in $N_{2}$ ambience by sol-gel method, using tetraethyl orthosilcate, lithium methoxide, zirconium n-propoxide, and tributyle phosphate as precursors. The prepared material was dried and crushed into powder, and it was pressed into disk type samples. These samples were sintered at $900^{\circ}C{\sim}1100^{\circ}C$ for 50 hours. The physical characteristics of the samples were investigated by TG/DTA, SEM, AES and XRD methods. $CO_{2}$ sensor based on lithium ionic solid electrolyte was fabricated and its operational characteristics were measured. The sensing characteristics of the sensor sintered at $1000^{\circ}C$ shows the variation of e.m.f. about $35{\sim}63\;mV/decade$ for the variation of $CO_{2}$ concentration at $200^{\circ}C{\sim}300^{\circ}C$ of operating temperature, and good linearity for $300{\sim}6000\;ppm$.

$60^{\circ}C$의 질소 분위기에서 tetraethyl orthosilcate, lithium methoxide, zirconium n-propoxide 그리고 tributyle phosphate를 전구체로 써서 sol-gel법으로 Li 이온-고체 전해질을 합성하였다. 합성한 물질을 건조하고 분쇄하여, 이를 가압 성형하여 원반형 시편들을 제조하였다. 시편들을 $900^{\circ}C{\sim}1100^{\circ}C$에서 50시간 열처리하였다. 시편들의 물성을 TG/DTA, SEM, AES 및 XRD 법으로 조사하였다. Li 이온 이온-고체 전해질을 이용한 $CO_{2}$ 가스 감지 소자를 제작하고 그 동작 특성을 측정하였다. 제작된 감지 소자 중에서 $1000^{\circ}C$에서 열처리한 경우, 동작 온도가 $200^{\circ}C{\sim}300^{\circ}C$ 일 때, $CO_{2}$ 농도 변화에 대해 $35{\sim}63mV/decade$의 기전력 변화를 나타내었고, $300{\sim}6000 ppm$까지 선형성이 우수하였다.