(1. 湖南大學(xué) 新型炭材料研究所，長沙 410082；
2. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 用化學(xué)聚合法合成聚苯胺(PAn)，并考察其在LiCoO2和LiMn2O4正極中的雙重功能。結(jié)果表明：在優(yōu)化條件下PAn的產(chǎn)率y=94.06%、導(dǎo)電率σ=18.39 S/cm，大于乙炔黑(AB)的導(dǎo)電率σ=7.77 S/cm；以制備的PAn為鋰離子電池正極活性材料，在不添加其他導(dǎo)電劑對其進(jìn)行恒電流充、放電試驗(yàn)(電流密度J=15 mA/g)時，第三循環(huán)的比放電容量D3=60.8 mA∙h/g、充、放電效率η3=94.56%；PAn在正極中兼有活性材料的功能；以LiCoO2和尖晶石LiMn2O4為正極活性材料，以PAn替代AB作為導(dǎo)電劑進(jìn)行恒電流充、放電試驗(yàn)，在電流密度分別為15、30、45和60 mA/g時，比充、放電容量都增大，表明正極的極化程度減小；正極在經(jīng)過較大電流密度(60 mA/g)充、放電后，再以小電流密度(15 mA/g)進(jìn)行充、放電時，比充、放電容量幾乎沒有變化，表明經(jīng)較大電流密度(60 mA/g)充、放電后，LiCoO2和尖晶石LiMn2O4的貯鋰結(jié)構(gòu)沒有改變。
關(guān)鍵字: 鋰離子電池；LiCoO2；LiMn2O4；聚苯胺；化學(xué)聚合；雙重功能
LiCoO2 and LiMn2O4
（1. Institute of New Carbon Materials, Hunan University, Changsha 410082, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Polyaniline (PAn) was produced by chemical polymerization. The dual function of PAn in positive electrodes of LiCoO2 and LiMn2O4 was investigated. The results show that under the optimized conditions, the yield of PAn is y=94.06% and its electronic conductivity is σ=18.39 S/cm, which is greater than that of acetylene black (AB) (σ=7.77 S/cm). The galvanostatic experiment (current density J=15 mA/g) with the above PAn as the positive electrode active material was carried out, and no other electronic conductive reagent was used. In the third cycle, the specific discharge capacity (D3) is 60.8 mA∙h/g, the charge and discharge efficiency η3 is 94.56%. PAn in the positive electrodes has the function of active materials. The galvanostatic experiments were carried out with the LiCoO2 and spinel LiMn2O4 as the positive electrode active materials and the PAn was used as the electronic conductive reagent to take place of AB. When the current densities are 15, 30, 45 and 60 mA/g, all the specific charge and discharge capacities increase. After charging and discharging with large current density (60 mA/g), the positive electrode charged and discharged with the original small current density (15 mA/g). The specific charge and discharge capacities are almost unchanged. It shows that the storing lithium ions structures of LiCoO2 and spinel LiMn2O4 do not change.
Key words: lithium ion batteries; LiCoO2; LiMn2O4; polyaniline; chemical polymerization; dual function
