Vertical graphene growth on uniformly dispersed sub-nanoscale SiOx/N-doped carbon composite microspheres with a 3D conductive network and an ultra-low volume deformation for fast and stable lithium-ion storage
Vertical graphene growth on uniformly dispersed sub-nanoscale SiOx/N-doped carbon composite microspheres with a 3D conductive network and an ultra-low volume deformation for fast and stable lithium-ion storage
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DOI：
10.1039/c9ta12554j
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发表时间：
2020-02-21
影响因子：
11.9
通讯作者：
Yu, Jie
中科院分区：
文献类型：
--
作者：
Han, Meisheng;Mu, Yongbiao;Yu, Jie
低价氧化硅（SiOx，x < 2）是一种很有前途的负极材料，由于其高的锂离子存储容量，在锂离子电池中得到了广泛的应用。然而，SiOx具有差的导电性并且经历大的体积变化，导致循环期间差的倍率性能和稳定性。本文中，通过在热化学气相沉积（CVD）条件下在密封容器中热解1，3-双（3-氨丙基）四甲基二硅氧烷获得的SiOCN微球上径向取向生长VG，容易地制备垂直石墨烯@SiOx/N掺杂碳（VG@SiOx/NC）复合材料。在CVD过程中，SiOCN微球转化为具有均匀分散的亚纳米级SiOx和NC的SiOx/NC微球。均匀分散在SiOx/NC球中的亚纳米级NC和表面VG构成了三维导电和坚固的网络，导致快速和稳定的锂离子嵌入/脱嵌。作为LIB阳极，VG@SiOx/NC复合材料显示出1323.8mA h g（-1）的高可逆容量、优异的倍率性能（20 A g（-1）下265.5mA h g（-1））和长循环寿命（在2A g（-1）下超过500次循环，容量保持率为84.2%）。
Silicon suboxide (SiOx, x < 2) is a promising candidate anode material, which has been widely used in lithium-ion batteries (LIBs) due to its high lithium-ion storage capacity. However, SiOx has poor conductivity and undergoes large volume change, resulting in poor rate capability and stability during cycling. Herein, a vertical graphene@SiOx/N-doped carbon (VG@SiOx/NC) composite is easily prepared by the radially oriented growth of VG on SiOCN microspheres obtained by the pyrolysis of 1,3-bis(3-aminopropyl)tetramethyldisiloxane in a sealed vessel under thermal chemical vapor deposition (CVD) conditions. The SiOCN microspheres are transformed into SiOx/NC microspheres with homogeneously dispersed SiOx and NC at the sub-nanoscale in the CVD process. The uniformly dispersed sub-nanoscale NC in the spheres of SiOx/NC and the surface VG construct a 3D conductive and robust network, resulting in fast and stable lithium ion intercalation/deintercalation. As an LIB anode, the VG@SiOx/NC composite shows a high reversible capacity of 1323.8 mA h g(-1), excellent rate performance (265.5 mA h g(-1) at 20 A g(-1)), and long cycling life (over 500 cycles with 84.2% of capacity retention at 2 A g(-1)).