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Artificial Composite Anode Comprising High‐Capacity Silicon and Carbonaceous Nanostructures for Long Cycle Life Lithium‐Ion Batteries
Author(s) -
Breitung Ben,
Schneider Artur,
Chakravadhanula Venkata Sai Kiran,
Suchomski Christian,
Janek Jürgen,
Sommer Heino,
Brezesinski Torsten
Publication year - 2018
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201700004
Subject(s) - silicon , materials science , anode , lithium (medication) , chemical engineering , carbon fibers , composite number , nanoparticle , nanotechnology , pyrolysis , electrode , composite material , optoelectronics , chemistry , medicine , engineering , endocrinology
The use of functional nanomaterials is a common strategy to improve the mechanical and electrochemical properties of silicon anodes for secondary lithium‐ion cells. Here, we report the preparation of a structurally stable composite material with a unique morphology comprising small‐size silicon particles and especially branched carbonaceous nanofibers and the analysis of its cycling performance by galvanostatic measurements. This two‐phase composite was obtained from pyrolysis of blended silicon/cyanamide powders. The conversion of cyanamide to turbostratic carbon, rather than graphitic carbon nitride, was unexpected and appears to be catalyzed by accidental iron nanoparticles. Although the carbon content after pyrolysis was only about 7 %, half‐cells using electrodes containing the silicon/carbon composite outperformed other silicon‐based anode materials tested herein in terms of cyclability. After 300 cycles, they delivered two times higher capacity (>1.7 A h g silicon −1 at C/10 and >0.5 A h g silicon −1 at 1C in the 600–30 mV range when operated in constant current mode) than cells of similar loading with pristine silicon particles. The average fade rate per cycle was around 0.1 % between the 10th and 300th cycles, which is notable considering that the electrode structure and composition have not yet been optimized for battery applications.