高分散SiO2/石油沥青基多孔碳用于锂离子电池负极

二氧化硅(SiO₂)作为锂离子电池负极材料具有理论容量高、放电电位低、成本较低等特点,但存在导电性差、充放电过程体积膨胀严重以及容量衰减过快等问题。以石油沥青为碳源,利用硅烷偶联剂KH-540对纳米α-Fe₂O₃模板剂进行表面化学包覆,然后将硅源修饰模板剂与碳源混合,经碳化、酸洗等步骤得到高分散SiO₂/石油沥青基多孔碳(SiO₂/PC)。所得SiO₂/PC作为锂离子电池负极材料,在1 A·g^-1电流密度下,循环900圈后仍具有640 mA·h·g^-1的高可逆比容量。研究结果表明,高度纳米化的SiO₂在高温碳化过程原位生成,紧密牢固地负载于多孔碳表面,提高了其导电性,同时能够有效缓解SiO₂在充放电过程中的体积膨胀,抑制SiO₂的团聚或粉化,从而表现出优异的电化学性能。     

A new rechargeable lithium-ion battery with a xLi2MnO3·(1 − x) LiMn0.4Ni0.4Co0.2O2 cathode and a hard carbon anode

We reported a new type of rechargeable lithium-ion battery consisting of a structurally integrated 0.4Li₂MnO₃·0.6LiMnNi_0.4Co_0.2O₂ cathode and a hard carbon anode. The drawback of the high irreversible capacity loss of both electrodes, occurring at the first charge/discharge process, can be counterbalanced each other. The battery shows good reversibility with a sloping voltage from 1.5 V to 4.5 V and delivers a capacity of 105 mA h g⁻¹ and a specific energy of 315 W h kg⁻¹ based on the total weight of the both active electrode materials.