醋酸纤维素基纳米炭纤维制备与电化学性能

Preparation and electrochemical performance of cellulose acetate-based carbon nanofibers

本文以醋酸纤维素(CA)为碳源、以PVP为添加剂,通过静电纺丝法制备CA/PVP纳米纤维,经PVP脱除、脱乙酰化、预氧化和炭化制备了醋酸纤维素基纳米炭纤维。通过扫描电镜、红外光谱和物理吸附等手段考察了PVP添加量对纤维形貌、分子结构、比表面积与孔结构等结构的影响。结果表明,乙醇浸泡成功脱除了CA/PVP纳米纤维中PVP,形成了丰富的中/大孔,而这些孔隙有效的促进了CA的脱乙酰化,进而有效提升了纤维炭化过程中的结构稳定性。过多添加PVP会导致CA相不连续,其脱除会导致CA骨架的坍塌融合。添加PVP后所得碳纳米纤维具有完好的纤维形态,比表面积可达454m^(2)/g。将所得纳米炭纤维用作电容器电极进行电化学测试,结果表明,当CA/PVP为1:1时,所得纳米炭纤维的电化学性能最优,其在0.2 A/g电流密度下的比电容为103 F/g。

In this work,CA-based carbon nanofibers/PVP were prepared by electrospinning with cellulose acetate(CA)as carbon source and PVP as additive,followed by PVP removal,deacetylation,preoxidation and carbonization.The effects of PVP addition on the morphology,molecular structure,specific surface area and pore structure of the CA-based nanofibers were investigated by means of SEM,IR and physical adsorption.The results showed that PVP in CA/PVP nanofibers was successfully removed by ethanol immersion,and abundant meso-/macropores were generated.These pores effectively promoted the deacetylation of CA,then improving the structural stability of the fibers during carbonization.And,excessive addition of PVP will lead to discontinuous CA phase,and its removal led to collapse and fusion of CA skeleton.With introduction of PVP,the as-prepared CA-based carbon nanofibers presented well fiber morphology,and their specific surface area reached 454 m^(2)/g.The CA-based carbon nanofibers were used as electrodes of supercapacitors for electrochemical testing.The results showed that when CA/PVP ratio was 1:1,the CA-based carbon nanofibers showed the best capacitive performance,which reached 103 F/g at 0.2 A/g.