1 research outputs found
Suppressed Volume Change of a Spray-Dried 3D Spherical-like Si/Graphite Composite Anode for High-Rate and Long-Term Lithium-Ion Batteries
Morphology plays a vital role in controlling the volume
variation
in Si-based anode materials and enhances lithium-ion battery performances.
Here, we demonstrated advanced techniques that combine electrostatic
self-assembly and spray-drying methods to form 3D spherical-like silicon/graphite
(denoted “Si/G”) composite anode materials. This spherical
morphology alleviates issues relating to silicon volume changes that
occur in high-rate lithium-ion batteries. Commercial graphite (G)
flakes were initially mixed with silicon nanoparticles (ca. 50 nm)
to form a bare-Si/G composite through electrostatic interaction; spherical-like
composite particles were then obtained through single and double spray-drying
processes, giving samples SD1-Si/G and SD2-Si/G, respectively. We
examined the charge/discharge characteristics of the fabricated electrodes
(CR2032-type coin cells) in the voltage range 0.02–1.5 V (vs Li/Li+). The as-fabricated bare-Si/G, SD1-Si/G,
and SD2-Si/G half-cells provided initial discharge specific capacities
of 897, 866, and 1020 mA h g–1, respectively. The
SD2-Si/G half-cell shows better cycling stability at a high current
rate of 400 mA g–1 than the SD1-Si/G and bare-Si/G
half-cells due to effective inhibition of the volume change in the
more stable spherical structure of the SD2-Si/G composite, as evidenced
through in situ dilatometry. Thus, the spherical
Si/G composite material produced through this simple spray-drying
process had structural characteristics that could effectively resist
silicon’s high expansion rate, lower the production rate of
broken silicon particles, and improve the electrochemical performance
of the anode