摘要
将钛酸四丁酯和氧化石墨超声分散于叔丁醇,微波辐射下加入醋酸锂溶液制备尖晶石Li4Ti5O12（LTO）前驱体/氧化石墨烯.一方面,微波作用促进了钛酸四丁酯水解,前驱体的形成能在15 min内完成.另一方面,叔丁醇的“软模板”限域作用导致形成粒子极小且形貌单一的LTO前驱体.同时,细小的LTO前驱体粒子通过二次团聚将氧化石墨烯纳米片完全包埋.最后,LTO前驱体/氧化石墨烯在800 ℃下煅烧8h得到尖晶石LTO@石墨烯（LTO@G）.研究表明,LTO@G晶体尺寸在0.2～1.5μm之间,其振实密度达到1.7 g·cm^-3.石墨烯位于晶体内部,并显著提高了材料的电子传导性.LTO@G的电导率为1.84×10^-3 S·m^-1,远高于纯相LTO（1.1×10^-7 S·m^-1）.1C和4C下,LTO@G首次充放电容量分别是170.1和97.5 mAh·g^-1.可见,LTO@G具有高倍率性能和振实密度,可广泛应用于各种商品锂离子电池.
Tetrabutyl titanate and graphite oxide were dispersed in tertbutanol by uhrasonication and then added the lithium acetate solution into the above mixed solution under the microwave radiation to produce spinel Li4Ti5O12 （LTO） precursor/graphene oxide. On the one hand, the microwave radiation will promote the hydrolysis of tetrabutyl titanate, thus the reaction for forming the precursor can be completed in 15 min. On the other hand, ＂soft template＂ confinement effect of tertbutanol leads to form the LTO precursor with very small particle size and uniform morphology. Meanwhile, small LTO precursor particles will fully embed the graphene oxide nanosheets through their second agglomeration. Finally, the LTO precursor/graphene oxide was calcined at 800 ℃ for 8 h to obtain spinel LTO@graphene （LTO@G）. The study shows that LTO crystal in the LTO@G has a diameter of 0.2-1.5μm and the tap density of LTO@G reached 1.7 g.cm^-3. The graphene is located inside the crystal and significantly improve the electronic conductivity. The conductivity of LTO@G was found to be 1.84× 10^-3 S.m^-1, which is remarkably higher than pure phase LTO （1.1×10^-7 S.m^-1）. In 1C and 4C, the first discharge specific capacitances of LTO@G was found to be 170.1 mAh·g^-1 and 97.5 mAh·g^-1, respectively. These results demonstrated that the LTO@G has good high-rate capability and tap density, it can be widely used in various commercial lithium ion battery.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2014年第12期2691-2698,共8页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.21176101)资助项目
