沥青基炭硅负极材料的合成及电化学性能研究  

Synthesis and electrochemical properties of pitch-based carbon-silicon anode materials

作　　者：刘曙民 陆佳欣 公绪春 王际童[1] Liu Shu-min;Lu Jia-xin;Gong Xu-chun;Wang Ji-tong(National Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China;Sinopec Jinan Branch,Shandong Jinan 250012,China)

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237 [2]中国石化济南分公司,山东济南250012

出　　处：《炭素技术》2024年第6期30-36,65,共8页Carbon Techniques

基　　金：国家自然科学基金面上项目(U21A2060,22178116,21978097)。

摘　　要：硅基负极材料具有比容量高(3579 mAh/g)和来源广泛的优势,但是充放电过程中产生的巨大体积效应(~300%)会导致材料性能衰减严重。多孔硅结构在体积膨胀的过程中可以借助内部孔隙缓解部分机械应力,避免材料的破裂粉碎,从而改善硅基负极的循环性能;但是高孔隙会降低负极材料的储锂能力,在形成SEI膜上消耗更多的Li^(+)。本实验选择微米硅铝合金为原料,酸蚀得到多孔硅,采用沥青甲苯可溶物作为炭前驱体浸渍处理,在多孔硅表面形成包覆,最后经过高温炭化得到“内外一体”的碳导电网络,作为锂离子电池负极材料,在0.2 A/g电流密度下的首圈理论比容量为1755.06 mAh/g,150圈后的稳定容量为915.19 mAh/g;倍率方面,随着电流密度的提高,其比容量阶梯式下降,在2.0 A/g下的比容量稳定在563.4 mAh/g,容量保持率相比于多孔硅PSi更高。Silicon-based anode materials have the advantages of high specific capacity(3579 mAh/g)and a wide range of sources,but the large volume effect(~300%)generated during charging and discharging will lead to severe degradation of material properties.In the process of volume expansion,the porous silicon structure can alleviate part of the mechanical stress with the help of internal pores,avoid the cracking and crushing of the material,and thus improve the cycling performance of the silicon-based anode,but the high porosity will reduce the lithium storage capacity of the anode material and consume more Li^(+)in the formation of SEI film.In this experiment,micron silicon-aluminum alloy was selected as raw material to prepare porous silicon by acid etching,and pitch toluene solubles were used as carbon precursors to impregnate in the pores of porous silicon.By surface coating,a carbon conductive network of“internal and external integration”was formed after high-temperature carbonization.When was used as the anode material of lithium-ion battery,the Si/C composite exhibits a theoretical specific capacity of 1755.06 mAh/g in the first cycles at a current density of 0.2 A/g,and a stable capacity of 915.19 mAh/g after 150 cycles.In terms of rate performance,with the increase of current density,its specific capacity decreases step by step,and the specific capacity is stable at 563.4 mAh/g at 2.0 A/g,and the capacity retention rate is higher than that of porous silicon PSi.

关 键 词：多孔硅 沥青浸渍 炭硅负极材料 电化学性能 

分 类 号：TQ522.65[化学工程—煤化学工程] TM911.15[电气工程—电力电子与电力传动]