PVC를 원료로 탄소코팅한 Li4Ti5O12의 합성 및 전기화학적 특성

현시철,나병기 한국청정기술학회 2018 청정기술 Vol.24 No.1

In this study, Li4Ti5O12 anode materials for lithium ion battery were synthesized by dry ball-mill method. Polyvinyl chloride (PVC) as a carbon source was added to improve electrochemical properties. When the PVC was added after Li4Ti5O12 formation, the spinel structure was well synthesized and it was confirmed by X-ray diffraction (XRD) experiments. When the carbon material was added before the synthesis and the heat treatment was performed, it was confirmed that a material having a different crystal structure was synthesized even when a small amount of carbon material was added. In the case of Li4Ti5O12 without the carbon material, the electrical conductivity value was about 10 μS m-1, which was very small and similar to that of the nonconductor. As the carbon was added, the electrical conductivity was greatly improved and increased up to 10,000 times. Electrochemical impedance spectroscopy (EIS) analysis showed that the size of semicircle corresponding to the resistance decreased with the carbon addition. This indicates that the resistance inside the electrode is reduced. According to the Cyclic voltammetry (CV) analysis, the potential difference between the oxidation peak and the reduction peak was reduced with carbon addition. This means that the rate of lithium ion insertion and deinsertion was increased. Li4Ti5O12 with 9.5 wt% PVC added sample showed the best properties in rate capabilities of 180 mA h g-1 at 0.2 C-rate, 165 mA h g-1 at 0.5 C-rate, and 95.8 mA h g-1 at 5 C-rate. 리튬이온전지의 음극활물질로 사용되는 Li4Ti5O12를 건식 볼밀법으로 합성하였고, Li4Ti5O12의 전기화학적 특성을 향상시키기 위하여 탄소소재인 polyvinyl chloride (PVC)를 첨가하였다. PVC는 Li4Ti5O12를 합성하고 난 후에 첨가하였을 때 스피넬구조를 갖는 물질이 잘 합성되었음을 X-ray diffraction (XRD) 실험으로 확인하였다. 합성하기 전에 탄소재를 첨가하여 열처리를 한 경우에는 탄소재가 미량 첨가되더라도 다른 결정구조의 물질이 합성되는 것을 확인할 수 있었다. 탄소재를 첨가하지 않은 Li4Ti5O12의 경우 전기전도도 값이 약 10 μS m-1으로 부도체에 가까운 매우 작은 값을 보였다. 탄소를 첨가함에 따라서 전기전도도가 크게 향상되었으며, 압력을 증가시킬 경우에 최대 10,000배 이상 증가되었다. Electrochemical impedance spectroscopy (EIS) 분석결과 탄소를 첨가할 경우 저항에 해당하는 반원의 크기가 감소하였으며, 이는 전극내의 저항이 감소하였음을 보여준다. Cyclic voltammetry (CV) 분석에 의하면 탄소를 첨가할 경우에 산화피크와 환원피크의 전위차가 줄어들었으며, 이는 리튬이온의 삽입과 탈리의 속도가 증가하였음을 의미한다. PVC를 9.5 wt% 첨가한 물질의 경우, 0.2 C-rate에서 180 mA h g-1, 0.5 C-rate에서 165 mA h g-1, 5C-rate에서 95.8 mA h g-1의 용량을 나타냄으로써 우수한 출력 특성을 보여주었다.

PVC를 원료로 탄소코팅한 Li₄Ti₅O₁₂의 합성 및 전기화학적 특성

현시철,나병기,Hyun, Si-Cheol,Na, Byung-Ki 한국청정기술학회 2018 청정기술 Vol.24 No.1

리튬이온전지의 음극활물질로 사용되는 $Li_4Ti_5O_{12}$를 건식 볼밀법으로 합성하였고, $Li_4Ti_5O_{12}$의 전기화학적 특성을 향상시키기 위하여 탄소소재인 polyvinyl chloride (PVC)를 첨가하였다. PVC는 $Li_4Ti_5O_{12}$를 합성하고 난 후에 첨가하였을 때 스피넬 구조를 갖는 물질이 잘 합성되었음을 X-ray diffraction (XRD) 실험으로 확인하였다. 합성하기 전에 탄소재를 첨가하여 열처리를 한 경우에는 탄소재가 미량 첨가되더라도 다른 결정구조의 물질이 합성되는 것을 확인할 수 있었다. 탄소재를 첨가하지 않은 $Li_4Ti_5O_{12}$의 경우 전기전도도 값이 약 $10{\mu}S\;m^{-1}$으로 부도체에 가까운 매우 작은 값을 보였다. 탄소를 첨가함에 따라서 전기전도도가 크게 향상되었으며, 압력을 증가시킬 경우에 최대 10,000배 이상 증가되었다. Electrochemical impedance spectroscopy (EIS) 분석결과 탄소를 첨가할 경우 저항에 해당하는 반원의 크기가 감소하였으며, 이는 전극내의 저항이 감소하였음을 보여준다. Cyclic voltammetry (CV) 분석에 의하면 탄소를 첨가할 경우에 산화피크와 환원피크의 전위차가 줄어 들었으며, 이는 리튬이온의 삽입과 탈리의 속도가 증가하였음을 의미한다. PVC를 9.5 wt% 첨가한 물질의 경우, 0.2 C-rate에서 $180mA\;h\;g^{-1}$, 0.5 C-rate에서 $165mA\;h\;g^{-1}$, 5C-rate에서 $95.8mA\;h\;g^{-1}$의 용량을 나타냄으로써 우수한 출력 특성을 보여주었다. In this study, $Li_4Ti_5O_{12}$ anode materials for lithium ion battery were synthesized by dry ball-mill method. Polyvinyl chloride (PVC) as a carbon source was added to improve electrochemical properties. When the PVC was added after $Li_4Ti_5O_{12}$ formation, the spinel structure was well synthesized and it was confirmed by X-ray diffraction (XRD) experiments. When the carbon material was added before the synthesis and the heat treatment was performed, it was confirmed that a material having a different crystal structure was synthesized even when a small amount of carbon material was added. In the case of $Li_4Ti_5O_{12}$ without the carbon material, the electrical conductivity value was about $10{\mu}S\;m^{-1}$, which was very small and similar to that of the nonconductor. As the carbon was added, the electrical conductivity was greatly improved and increased up to 10,000 times. Electrochemical impedance spectroscopy (EIS) analysis showed that the size of semicircle corresponding to the resistance decreased with the carbon addition. This indicates that the resistance inside the electrode is reduced. According to the Cyclic voltammetry (CV) analysis, the potential difference between the oxidation peak and the reduction peak was reduced with carbon addition. This means that the rate of lithium ion insertion and deinsertion was increased. $Li_4Ti_5O_{12}$ with 9.5 wt% PVC added sample showed the best properties in rate capabilities of $180mA\;h\;g^{-1}$ at 0.2 C-rate, $165mA\;h\;g^{-1}$ at 0.5 C-rate, and $95.8mA\;h\;g^{-1}$ at 5 C-rate.

PVC를 원료로 탄소코팅한 Mo₆S₈의 합성 및 전기화학적 특성

현시철,조병원,나병기,Si-Cheol Hyun,Byung-Won Cho,Byung-Ki Na 한국화학공학회 2023 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.61 No.3

Magnesium secondary batteries are attracting much attention due to their potential to replace conventionally used lithium ion batteries. Magnesium secondary battery cathode material Mo₆S₈ were synthesized by molten salt synthesis method and PVC as a carbon materials were added to improve electrochemical properties. Crystal structure, size and surface of the synthesized anode materials were measured through XRD and SEM. Charge-discharge profiles and rate capabilities were measured by battery test system. 2.81 wt% PVC coated sample showed the best rate capabilities of 85.8 mAh/g at 0.125 C-rate, 69.2 mAh/g at 0.5 C-rate, and 60.5 mAh/g at 1 C-rate.

PVC를 원료로 탄소코팅한 Li₄Ti<SUB>5</SUB>O<SUB>12</SUB>의 합성 및 전기화학적 특성

현시철(Si-Cheol Hyun),나병기(Byung-Ki Na) 한국청정기술학회 2018 청정기술 Vol.24 No.1

리튬이온전지의 음극활물질로 사용되는 Li₄Ti5O12를 건식 볼밀법으로 합성하였고, Li₄Ti5O12의 전기화학적 특성을 향상시키기 위하여 탄소소재인 polyvinyl chloride (PVC)를 첨가하였다. PVC는 Li4Ti5O12를 합성하고 난 후에 첨가하였을 때 스피넬구조를 갖는 물질이 잘 합성되었음을 X-ray diffraction (XRD) 실험으로 확인하였다. 합성하기 전에 탄소재를 첨가하여 열처리를 한 경우에는 탄소재가 미량 첨가되더라도 다른 결정구조의 물질이 합성되는 것을 확인할 수 있었다. 탄소재를 첨가하지 않은 Li₄Ti5O12의 경우 전기전도도 값이 약 10 μS m<SUP>-1</SUP>으로 부도체에 가까운 매우 작은 값을 보였다. 탄소를 첨가함에 따라서 전기전도도가 크게 향상되었으며, 압력을 증가시킬 경우에 최대 10,000배 이상 증가되었다. Electrochemical impedance spectroscopy (EIS) 분석결과 탄소를 첨가할 경우 저항에 해당하는 반원의 크기가 감소하였으며, 이는 전극내의 저항이 감소하였음을 보여준다. Cyclic voltammetry (CV) 분석에 의하면 탄소를 첨가할 경우에 산화피크와 환원피크의 전위차가 줄어들었으며, 이는 리튬이온의 삽입과 탈리의 속도가 증가하였음을 의미한다. PVC를 9.5 wt% 첨가한 물질의 경우, 0.2 C-rate에서 180 mA h g<SUP>-1</SUP>, 0.5 C-rate에서 165 mA h g<SUP>-1</SUP>, 5C-rate에서 95.8 mA h g<SUP>-1</SUP>의 용량을 나타냄으로써 우수한 출력 특성을 보여주었다. In this study, Li₄Ti5O12 anode materials for lithium ion battery were synthesized by dry ball-mill method. Polyvinyl chloride (PVC) as a carbon source was added to improve electrochemical properties. When the PVC was added after Li₄Ti5O12 formation, the spinel structure was well synthesized and it was confirmed by X-ray diffraction (XRD) experiments. When the carbon material was added before the synthesis and the heat treatment was performed, it was confirmed that a material having a different crystal structure was synthesized even when a small amount of carbon material was added. In the case of Li₄Ti5O12 without the carbon material, the electrical conductivity value was about 10 μS m<SUP>-1</SUP>, which was very small and similar to that of the nonconductor. As the carbon was added, the electrical conductivity was greatly improved and increased up to 10,000 times. Electrochemical impedance spectroscopy (EIS) analysis showed that the size of semicircle corresponding to the resistance decreased with the carbon addition. This indicates that the resistance inside the electrode is reduced. According to the Cyclic voltammetry (CV) analysis, the potential difference between the oxidation peak and the reduction peak was reduced with carbon addition. This means that the rate of lithium ion insertion and deinsertion was increased. Li₄Ti5O12 with 9.5 wt% PVC added sample showed the best properties in rate capabilities of 180 mA h g<SUP>-1</SUP> at 0.2 C-rate, 165 mA h g<SUP>-1</SUP> at 0.5 C-rate, and 95.8 mA h g<SUP>-1</SUP> at 5 C-rate.