Chitosan complements entrapment of silicon inside nitrogen doped carbon to improve and stabilize the capacity of Li-ion batteries

Abstract

A facile strategy to entrap milled silicon (m-Si) particles using nitrogen-doped-carbon (N-C@m-Si) to overcome the dramatic volume changes in Si during intercalation of lithium ions and to improve its electronic conductivity is reported here. The only natural nitrogen containing biomaterial alkaline polysaccharide, i.e., chitosan, is used as the carbon source. Simple hydrothermal technique followed by a subsequent carbonization process is used to synthesize N-C and N-C@m-Si particles. N-C@m-Si exhibited significantly improved electrochemical performance as compared to bare m-Si, which is confirmed by the obtained discharge capacity of 942.4 mAh g −1 and columbic efficiency of 97% after 50 cycles at 0.1C rate. With regard to the N-C electrodes, the obtained discharge capacity of 485.34 mAh g −1 and columbic efficiency of 99.78%, after 50 cycles at 0.1C rate is superior to the commercial graphite electrodes. The solid electrolyte interphase (SEI) layer that formed over m-Si and N-C@m-Si electrodes is characterized using X-ray photoelectron spectroscopy. Compared to the SEI layer that formed over m-Si electrode after 10 charge-discharge cycles, the N-C@m-Si electrode had a stable lithium fluoride and carbonate species. Brief reaction mechanisms, representing the formation of different species in the SEI layer, is derived to explain its behavior during the electrochemical processes.

Micron-Sized SiOx-Graphite Compound as Anode Materials for Commercializable Lithium-Ion Batteries

“…The right shift of the semi-circle in the Nyquist plot shows increased overpotential in electrolyte due to its depletion, and the increased size of the semi-circle is indicative of increased overpotential due to SEI information. However, although it exhibited gradual thickened SEI, the SEI showed dense and robust characteristics in HR-TEM images, which is contrary to the conventional feature of coarse and loose structure in ordinary silicon anodes [36,37]. This result corresponds with electrode swelling data and the surface state of the electrode in Figures 3 and S4.…”

Biochar for agronomy, animal farming, anaerobic digestion, composting, water treatment, soil remediation, construction, energy storage, and carbon sequestration: a review

“…The silicon and nitrogen modified electrode outperformed milled silicon in terms of electrochemical performance, with a discharge capacity of 0.940 × 10 3 mAh g −1 and a columbic efficiency of 97% over 50 cycles. After 50 cycles, the nitrogen modified electrode outperformed conventional graphite electrodes in discharge capacity and columbic efficiency, with a discharge capacity of 0.49 × 10 3 mAh g −1 and a columbic efficiency of 99.8% (Prasanna et al 2019 ).…”

Enhancing the performance of hard carbon for sodium-ion batteries by coating with silicon nitride/oxycarbide nanoparticles

“…The presence of similar O-Si-O peaks have been observed in XPS studies of silicon electrodes in lithium cells, where they were attributed to reactions of amorphous silicon with the carbonate electrolytes during formation of a solidelectrolyte interphase (SEI) layer. 76,78 It is likely that some fraction of our amorphous SiN x and SiOC particles were reduced to amorphous silicon during electrochemical reduction, but that the particle surfaces then reacted with the electrolyte to produce SiO x species. The continuous high capacity during cycling suggests that this is a surface effect that is deep enough for the etching that was carried out to not remove it completely, but not a major fraction of the active material.…”