以竹炭负载MnS、S复合材料为正极的锂硫电池

Lithium/sulfur battery with MnS,sulfur encapsulated bamboo charcoal composite as cathode

为提高锂硫电池的循环性能,采用水热法制备负载有硫化锰（MnS）的竹炭（BC）复合材料MnS@BC,通过热复合获得负载S的BC复合材料S-BC和负载S、MnS的BC复合材料S-MnS@BC。SEM和XRD分析表明：MnS@BC中MnS可填充BC表面的孔洞,并呈不均匀分布;没有出现MnS的衍射峰。电化学性能测试结果表明：负载于BC上的MnS本身没有电化学活性,但对多硫离子的氧化还原过程有催化作用,可提高电极的可逆性。S-MnS@BC复合材料电极以100 m A/g的电流在1.5~3.0 V充放电,首次放电比容量为1 346.1 m Ah/g,第50次循环的放电比容量保持在504.0 m Ah/g,在同等条件下的性能好于S-BC复合材料,表现出较轻的“飞梭效应”和较好的循环性能。

In order to improve the cycle performance of lithium/sulfur battery, manganese sulfide （MnS） encapsulated in bamboo charcoal（BC） composites（ MnS@ BC） was prepared by hydrothermal method. S encapsulated BC composites （S-BC） and S, MnS encapsulated BC composites（ S-MnS@ BC） were prepared by heat treatment. Results of XRD and SEM analyses showed that parts of holes at the surface of BC were filled by MnS and MnS distributed heterogeously at the holes of BC. There was no diffraction peaks of MnS. Electrochemical test results showed that although MnS imbedded in BC showed no electrochemical activity,it had catalytic effect in the redox process of polysulfides, thus the reversibility of cathode was enhanced. When assembling cell with composite charged and discharged between 1.5 - 3. 0 V with the current of 100 mA/g,the specific discharge capacity of the S-MnS@ BC composite was 1 346. 1 mAh/g in the initial cycle and remained 504. 0 mAh/g at the 50th cycle,which was higher than that of S-BC composite tested at the same condition. S-MnS@ BC composite showed less ＂shuttle effect＂ and better cycle performance.