石油沥青和葡萄糖热解炭的可逆储钠性能研究

Performance of pitch and glucose pyrocarbons for reversible sodium storage

以石油沥青和葡萄糖为原料,在氮气保护下采用高温热解的方法制备了沥青热解炭和葡萄糖热解炭负极材料。结果表明,葡萄糖热解炭比沥青热解炭层间距大、无定形程度大且含氧量多。葡萄糖热解炭首次放电容量171.9 mAh/g,沥青热解炭首次放电容量为79.2 mAh/g。20次循环以后葡萄糖热解炭和沥青热解炭容量保持率分别为94.6%和68.2%。循环伏安分析表明,沥青热解炭在低电位下的不可逆还原峰的出现电位更低,比葡萄糖热解碳降低了0.13 V。交流阻抗分析表明葡萄糖热解炭的SEI膜阻抗、界面阻抗及扩散阻抗均明显小于沥青热解炭。

Pitch and glucose pyrocarbons were prepared by the carbonization of petroleum pitch and glucose at 800 益 under a ni-trogen flow and were used as the electrodes of sodium ion batteries. Results show that the carbon interlayer spacing,and the oxygen content of the glucose carbon are much larger than those of the pitch carbon, while the degree of crystallinity is smaller. The first discharge capacities of the glucose and pitch carbons are 171.9 and 79. 2 mAh/g,and their capacity retention rates after 20 cycles are 94. 6 and 68. 2% , respectively. Cyclic voltammetry analysis shows that the potential of the irreversible reduction peak in the low potential range of the pitch pyrocarbon is lower than that of the glucose pyrocarbon. AC impedance analysis shows that the imped-ance of a solid-electrolyte interface film, the interface impedance and the diffusion resistance of the glucose pyrocarbon are signifi-cantly lower than that of the pitch pyrocarbon.