OBJECTIVES

1. Sulfur-Infiltrated Porous Carbon Microsphere with Controllable Multi-modal Pore Size Distribution for High Energy Lithium-Sulfur Batteries Cunyu Zhao, Lianjun Liu, Huilei Zhao, Andy Krall, Ying Li * Mechanical Engineering Department, University of Wisconsin-Milwaukee, Wisconsin, 53211 www.nature.com BACKGROUND Current Li-ion battery (LIBs) technology Sate-of-art LIBs: 150 Wh/kg, LIBs does not meet the requirements for large energy storage applications such as electric vehicles (EVs). The major obstaclelies in the cathode—using heavy transition metals. Li-S batteryholds great promise for achieving the goal of EV applications because elemental sulfur has the highest theoretical energy density (2,600 Wh/kg)andcapacity (1,675 mAh/g)of all known cathodes. Major hurdles in Li-S battery: (a) Highly insulating nature of sulfur-poor electrical conductivity (b) Solubility of reaction intermediates lithium polysulfides in electrolyte-loss of active sulfur mass over charge-discharge cycles. Solutions: Cathode Modification. OBJECTIVES EXPERIMENTAL • To use a novel and inexpensive method to fabricate S/C composites • with hierarchical structures as cathode materials for Li-S batteries. • porous microsphere framework with controlled pore size distribution Dr. Ying Li Phone: 414-229-3716 Email: liying@uwm.edu

2. Sulfur-Infiltrated Porous Carbon Microsphere with Controllable Multi-modal Pore Size Distribution for High Energy Lithium-Sulfur Batteries Cunyu Zhao, Lianjun Liu, Huilei Zhao, Andy Krall, Ying Li * Mechanical Engineering Department, University of Wisconsin-Milwaukee, Wisconsin, 53211 MATERIAL CHARACTERIZATION SEM Images of PMC/S X-ray diffraction patterns PMC/S-40 PMC/S-40:10 PMC/S-10 2θ = 23.4˚ and 28.0˚: orthorhomic phase sulfur. 2θ = 23.0˚: partially graphitized carbon structure in PMC. Sulfur------highly dispersed inside the pores of the carbon microsphere. 500nm Sulfur can be observed on the SEM images of PMC/S. EDX Analysis of PMC/S-40 SEM Images of C/SiO2 and PMC Surface PMC-40:10 PMC-40 C/SiO2-40 PMC-10 Silica is removed according to the appearance of PMC and was proved by both EDX and TGA. 40nm and 10nm size pores can be observed on PMC-40:10. Only 10 nm size pores can be seen on PMC-10 samples. PMC-10 PMC-40:10 Sulfur Carbon 200nm

3. Sulfur-Infiltrated Porous Carbon Microsphere with Controllable Multi-modal Pore Size Distribution for High Energy Lithium-Sulfur Batteries Cunyu Zhao, Lianjun Liu, Huilei Zhao, Andy Krall, Ying Li * Mechanical Engineering Department, University of Wisconsin-Milwaukee, Wisconsin, 53211 MATERIAL CHARACTERIZATION PMC-40:10 has a high specific surface area of 2485 m2/g. There are micropores(1.5nm), mesopores (6 nm, 10 nm, 30-44 nm) and macropores (55 nm) on PMC-40:10. PMC/S surface area decreased comparing with PMC, indicating sulfur infiltration into the PMC. N2 isotherms and pore size distribution ELECTRALCHEMICAL PERFORMANCE TEST CONCLUSION • Successfully synthesized multi-modal PMC/S using a relatively simple and inexpensivemethod that can be easily scaled-up. • The pore structure is easily controllableby adjusting the SiO2 NP template size and concentration. • Sulfur is well dispersed and confined in the porous carbon framework • The PMC/S-40:10 performs better than PMC/S-40 and PMC/S-10 – due to the unique combination of macropore, mesopore, and micropore structure that accommodate sulfur infiltration and volume expansion and prevent polysulfide from escaping the framework. Cyclability of PMC/S-40, PMC/S-10, PMC/S-40:10 and pristine sulfur Rate capability of PMC/S-40, PMC/S-10, PMC/S-40:10 and pristine sulfur PMC/S-40:10 performed the highest initial capacity of 1278 mAh/g and Coulombic efficiency of 90%. PMC/S-40:10 performed a better rate capability comparing with PMC/S-40 and PMC/S-10.