Carbon Materials Obtained From Waste Tires And Its Application For Lithium-sulfur Batteries

In this thesis,waste tires were used as the carbon source to design and prepare the rubber porous carbon(RPC).RPC was used to modify separator of lithium-sulfur battery to decrease the shuttle effect during the charge/discharge process of battery and improve the electrochemical performance of battery.The main research contents are as follows:(1)First of all,the influence of calcination temperature on RPC has been detected.The results exhibited that temperature influences the construction and composition of the porous carbon materials.The high specific area and high conductivity of RPC would be achieved under a high temperature.When the temperature reached 850℃,high content of oxygen,nitrogen and sulfur in the RPC would be obtained.In the meantime,higher conductivity(0.109 S/m)is achieved.(2)The as-prepared carbon materials were adopted to modify the separator.This modified separator absorbs the polysulfide generating during charge/discharge process and suppresses the shuttle effect;therefore,the modified separator enhances the electrochemical performance of lithium-sulfur batteries.After 200 cycles at the rate of 2C,the capacity of the battery with modified separator was 553.2mA·h·g-1 and coulombic efficiency stably maintained above 95.1%.The electrochemical performance of the battery with modified separator is better than that of the battery with AB modified separators.(3)The RPC modified separators could successfully be applied to battery with high sulfur content up to 77 wt%.Under the current density of 0.5 C,the initial specific capacity of the RPC reached 1006.4 mAh g-1 at high sulfur loading of 2.34 mg cm-2.And after 100 cycles,discharge capacity of the battery with the modified separator still achieved 641.6 mAh g-1,and the loop retention is 63.8%.The results show the battery with the modified separator has high cycling performance and high structural stability.