The lithium ion battery (LIB) has been the exclusive power source of portable electronic equipment because it holds the high power density and energy density among the known battery systems. However, the LIB is limited in large-scale applications, such as electric vehicles, plug-in hybrid electric v...
The lithium ion battery (LIB) has been the exclusive power source of portable electronic equipment because it holds the high power density and energy density among the known battery systems. However, the LIB is limited in large-scale applications, such as electric vehicles, plug-in hybrid electric vehicles, and energy storage systems, based on the cost, safety, and energy density. Therefore, alternatives for large format applications have been investigated. In particular, the lithium-sulfur (Li-S) battery has attracted much interest due to various advantages. The elemental sulfur used in the cathode active material for a Li-S battery is lightweight and has a reasonable cost because it is abundant in nature. The sulfur cathode can also provide a high theoretical capacity of 1672 mAh g-1, which is approximately five times higher than that of pre-existing commercial LIB. In addition, the energy density of a Li-S battery is as high as 2600 Wh kg-1. However, the system has serious problems, including active material loss, the poor electrical conductivity (5 × 10-30 S cm-1 at 25℃) of sulfur, and low system efficiency. Most of these issues result from the shuttle reaction undergone by the intermediate products of Li-S discharge. Recently, to overcome these obstacles for commercial use of Li-S batteries, a variety of strategies have been investigated including the preparation of sulfur-conductive material composites, electrode surface modification, and optimization of the organic electrolyte or separator.
In this study, a simple and effective methode using a pelletizing-heat treatment process has been proposed for the preparation of the sulfur/carbon (S/C) composite. This method improved the distribution of sulfur in the S/C composite and resulted in an increase in the electrical conductivity of the S/C composite. The electrical conductivity of the P-S/CNT composite is higher than those of S/CNT and H-S/CNT due to the even distribution of sulfur and the contact between the sulfur particles. The electrical conductivities of the S/CNT, H-S/CNT, and P-S/CNT composites are 10.84, 10.03, and 12.98 S m-1 at 10 MPa, respectively. Morphologically different carbons, such as multi-walled carbon nanotube (MWCNT), acetylene black (AB), and graphene nanosheet (GNS), have been employed to prepared th S/C composites to wrap the sulfur particles usisng the method proposed in this study, and their performances as a cathode for a rechargeable Li-S battery have been discussed. In the cyclic voltammetric (CV) curves of P-S/CNT, no change in the CV peak position and current intensity was observed for up to ten cycles. In addition, the discharge capacities of the P-S/CNT, P-S/AB, and P-S/GNS electrodes are 1166, 924, and 960 mAh g-1 at 1st cycle, and 806, 514, and 655 mAh g-1 after 40 cycles, respectively. These results suggest that the geometric structure of carbon plays an important role in the suppression of active material loss, leading to the improved performance of Li-S battery.
The lithium ion battery (LIB) has been the exclusive power source of portable electronic equipment because it holds the high power density and energy density among the known battery systems. However, the LIB is limited in large-scale applications, such as electric vehicles, plug-in hybrid electric vehicles, and energy storage systems, based on the cost, safety, and energy density. Therefore, alternatives for large format applications have been investigated. In particular, the lithium-sulfur (Li-S) battery has attracted much interest due to various advantages. The elemental sulfur used in the cathode active material for a Li-S battery is lightweight and has a reasonable cost because it is abundant in nature. The sulfur cathode can also provide a high theoretical capacity of 1672 mAh g-1, which is approximately five times higher than that of pre-existing commercial LIB. In addition, the energy density of a Li-S battery is as high as 2600 Wh kg-1. However, the system has serious problems, including active material loss, the poor electrical conductivity (5 × 10-30 S cm-1 at 25℃) of sulfur, and low system efficiency. Most of these issues result from the shuttle reaction undergone by the intermediate products of Li-S discharge. Recently, to overcome these obstacles for commercial use of Li-S batteries, a variety of strategies have been investigated including the preparation of sulfur-conductive material composites, electrode surface modification, and optimization of the organic electrolyte or separator.
In this study, a simple and effective methode using a pelletizing-heat treatment process has been proposed for the preparation of the sulfur/carbon (S/C) composite. This method improved the distribution of sulfur in the S/C composite and resulted in an increase in the electrical conductivity of the S/C composite. The electrical conductivity of the P-S/CNT composite is higher than those of S/CNT and H-S/CNT due to the even distribution of sulfur and the contact between the sulfur particles. The electrical conductivities of the S/CNT, H-S/CNT, and P-S/CNT composites are 10.84, 10.03, and 12.98 S m-1 at 10 MPa, respectively. Morphologically different carbons, such as multi-walled carbon nanotube (MWCNT), acetylene black (AB), and graphene nanosheet (GNS), have been employed to prepared th S/C composites to wrap the sulfur particles usisng the method proposed in this study, and their performances as a cathode for a rechargeable Li-S battery have been discussed. In the cyclic voltammetric (CV) curves of P-S/CNT, no change in the CV peak position and current intensity was observed for up to ten cycles. In addition, the discharge capacities of the P-S/CNT, P-S/AB, and P-S/GNS electrodes are 1166, 924, and 960 mAh g-1 at 1st cycle, and 806, 514, and 655 mAh g-1 after 40 cycles, respectively. These results suggest that the geometric structure of carbon plays an important role in the suppression of active material loss, leading to the improved performance of Li-S battery.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.