Recent development of Sn–Fe-based materials as a substitute for Sn–Co–C anodes in Li-ion batteries: a review

Abstract

Tin based alloy materials have been widely studied as alternative anodes to replace the graphite anode in high energy density lithium-ion batteries (LIBs) due to their higher specific capacity and moderate lithiation potentials. Since 2005, Sony Company has applied a ternary Sn–Co–C alloy anode in an LIB with the trademark “Nexelion”, which has 30% increase in capacity and 20% increase in volumetric energy density in comparison to the conventional cells using graphite anodes. However, the high cost of Co, difficulties in preparing amorphous materials and unsatisfactory lifetime of this anode material have inhibited the wide commercialization of the “Nexelion” battery. Thus, in the past decade, intensive investigations have been focused on Sn–Fe and especially Sn–Fe–C alloy anodes using abundant and inexpensive Fe element. In this review, the advances of the Sn–Co and then Sn–Fe alloy based composite as anode materials for LIBs have been reviewed in detail, including the structural optimizations, preparation methods and enhancements in electrochemical performance. It is aimed to demonstrate that the cycling performance of Sn–Fe–C anode materials can be significantly enhanced by rational design of both the compositions and crystal structures of Sn–Fe intermetallic phases, and the dispersive state, morphology and surface features in the carbonaceous matrix. These concepts and strategies could also be beneficial for solving the cycling stability issue of other alloy-type anode materials in advanced metal-ion batteries for practical applications.