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以聚苯乙烯(PS)胶晶作为铸模,采用纳米铸造工艺及后续煅烧的方法合成了三维有序大孔Fe_2SiO_4/SiO_2@C纳米玻璃陶瓷锂离子电池负极材料。溶胶-凝胶工艺产生的凝胶在650℃氩气氛炉中煅烧后,Fe_2SiO_4纳米晶体从含铁元素的SiO_2基玻璃中结晶析出,形成由Fe_2SiO_4纳米晶体、铁离子(Fe3+)修饰的玻璃态SiO_2和非晶碳组成的三维有序大孔纳米玻璃陶瓷。在50 m A·g~(-1)电流密度下进行充放电时,其放电容量可达450 m Ah·g~(-1)以上,电流密度增加到250 m A·g~(-1)时可逆放电容量仍旧稳定地保持在260 m Ah·g~(-1),而具有同样有序大孔结构和含碳量的非晶态SiO_2@C材料的放电比容量在50 m A·g~(-1)电流密度时仅为15 m Ah·g~(-1)。这些结果表明,Fe_2SiO_4纳米晶体及Fe~(3+)有助于SiO_2基玻璃陶瓷实现可逆储锂过程。
Polystyrene (PS) colloidal crystals were used as the molds to synthesize three-dimensionally ordered macroporous Fe_2SiO_4 / SiO_2 @ C nanoscale glass-ceramic anode materials for lithium-ion batteries using nano-casting and subsequent calcinations. After the gel produced by the sol-gel process is calcined in an argon atmosphere at 650 ° C, the Fe 2 SiO 4 nanocrystals crystallize out of the SiO 2 -based glass containing iron and form a glassy SiO 2 glass modified by Fe 2 SiO 4 nanocrystals and iron ions (Fe 3+) And amorphous carbon composed of three-dimensional ordered macroporous nano-glass ceramic. At discharge current of 50 m A · g -1, the discharge capacity can reach 450 m Ah · g -1 and the current density increases to 250 m A · g -1. The reversible discharge capacity remained stable at 260 m Ah · g -1, while the discharge capacity of amorphous SiO_2 @ C with the same ordered macroporous structure and carbon content was 50 m A · g ~ (-1) current density is only 15 m Ah · g ~ (-1). These results show that Fe 2 SiO 4 nanocrystals and Fe 3+ contribute to the reversible lithium storage of SiO 2 -based glass ceramics.