In order to solve the aforementioned problems, great efforts have been made to suppress the volume expansion–contraction of Si anode and improve the structure stability, such as constructing porous nanostructure, nanosizing Si particles, using Si-based alloy, and coating a buffer layer ( Lai et al., 2012 Lu et al., 2015 Woltornist et al., 2017 Han et al., 2020). Nevertheless, the extremely huge volume expansion/contraction (∼300%) in the lithiation/delithiation process has impeded the application of Si anode, which leads to the pulverization of bulk particles and deteriorates the long-term cycle life ( Chan et al., 2008 Liu et al., 2014 Li et al., 2016 Cook et al., 2017). In recent years, Si is regarded as one of the most potential anode materials for the next-generation lithium-ion batteries in virtue of the eminent specific capacity (∼4,200 mAh g −1) and low delithiation potential (∼0.4 V vs. Nevertheless, graphite fails to satisfy the increasing energy density requirements as a result of the limited discharging capacity (the theoretical value of LiC 6 = 372 mAh g −1). Currently, graphite is still the most commonly used anode material for lithium-ion batteries, due to the advantages of high initial Coulombic efficiency, long life, non-toxicity, and low cost compared with other candidate materials ( Yoshio et al., 2006 Khomenko et al., 2007 Yabuuchi et al., 2011 Yan et al., 2016). With the increasing energy/power density requirements and environmental problems in practical applications, it is critical to further improve electrochemical performances of the lithium-ion battery and reduce its price.
CORE SHELL PORTABLE
The lithium-ion battery is currently one of the high-performance rechargeable batteries in energy storage field, which has been commercialized and used in the portable electronic markets, renewable energy applications, and large-scale energy storage systems ( Li et al., 2018 Lu et al., 2018 Lyu et al., 2020 Zhang et al., 2020). This work paves an effective way to develop Si-based anodes for high-energy density lithium-ion batteries. Even if the current density reaches up to 2,000 mA g −1, the capacity can still be maintained at 1,173 mAh g −1. As expected, x/C anode maintains the excellent discharge capacity of 1,333 mAh g −1 after 100 cycles at a current density of 100 mA g −1. The SiO x/C shell not only ensures the structure stability and proves the high electrical conductivity but also prevents the penetration of electrolytes, so as to avoid the repetitive decomposition of electrolytes on the surface of Si particle. Herein, to reduce the volume change and improve the electrochemical performance, a novel x/C anode with a core–shell structure is designed by spray and pyrolysis methods. However, a Si anode is subjected to the huge volume expansion–contraction in the charging–discharging process, which can touch off pulverization of the bulk particles and worsens the cycle life. In the critical situation of energy shortage and environmental problems, Si has been regarded as one of the most potential anode materials for next-generation lithium-ion batteries as a result of the relatively low delithiation potential and the eminent specific capacity. 3College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, China.2Inner Mongolia Key Laboratory of Graphite and Graphene for Energy Storage and Coating, Hohhot, China.1School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot, China.
Xuelei Li 1,2, Wenbo Zhang 1,2, Xiaohu Wang 1,2, Wanming Teng 1,2, Ding Nan 1,2,3*, Junhui Dong 1,2, Liang Bai 1,2 and Jun Liu 1,2*
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