Mid Sweden University

To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.

Silicon anodes are considered as promising electrode materials for next-generation high-capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge−discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in the recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nano graphite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.