Silicon–Carbon Core–Shell Hollow Nanotubular Configuration High-Performance Lithium-Ion Anodes

Abstract

Silicon anode systems, due to their intrinsic high theoretical specific capacity, show tremendous potential in lithium ion batteries (LIBs). Unfortunately, commercial application still remains elusive due to the cycling-related colossal volume expansion issues following Li alloying and dealloying. Herein, core–shell C@Si@C hollow nanotubes with optimal Si thickness (∼60 nm) showing no microstructural damage during lithiation and delithiation processes, have been developed as a stable anode for LIBs with low first-cycle irreversible loss (FIR) of ∼13% and high areal capacity (∼3 mAhcm–2) for the first time. The hollow Si nanotubes (h-SiNTs) have been generated via our previously reported high-throughput and recyclable, sacrificial MgO wire template fabrication approach. Generation of Si films of varying thickness by low-pressure thermal chemical vapor deposition (LPCVD) with subsequent etching yields h-SiNTs. Modification/optimization of the h-SiNT physical characteristics exhibit improved performance in LIBs. Carbon coating of optimized h-SiNTs further, yields core–shell h-SiNTs for the first time exhibiting not only low FIR loss of ∼13%, with a specific capacity of ∼1000 mA·h·g–1 at discharge/charge currents of ∼1 A·g–1 for over 120 cycles, but also a low fade rate of ∼0.072% loss per cycle.