Pre-lithiated carbon-coated Si/SiOx nanospheres as a negative electrode material for advanced lithium ion capacitors

Abstract

A high-performance lithium ion capacitor (LIC) composed of activated carbon (as the positive electrode) and pre-lithiated C-coated Si/SiOx nanospheres (as the negative electrode) is investigated as a potential energy storage system for high-power and high-energy applications. Under optimized pre-lithiation conditions, the feasibility of pre-lithiated C-coated Si/SiOx nanospheres is thoroughly examined as an advanced negative electrode compared with a conventional graphite LIC using pre-lithiated C-coated Si/SiOx nanospheres. The pre-lithiated C-coated Si/SiOx nanospheres show much improved reversible capacity and rate capability with higher capacity retention at a high current density of 10C up to 1000 cycles compared with a conventional LIC. Such improvements may be attributed to the unique physical and chemical properties of C-coated Si/SiOx nanospheres. We believe that this approach provides a practical guideline for developing and successfully implementing advanced LICs.