Anode behavior of Sn/WC/graphene triple layered composite for lithium-ion batteries

Sn/WC/graphene (Sn/WC/G) triple layered composite in which Sn thin-layer (3-10 nm) enwrapped in-between WC (tungsten carbide) substrate and few-layer graphene is prepared via a simple two-step ball-milling approach. The as prepared triple layered composite exhibits superior cyclability with high capacity and rate capability in lithium-ion half cells, i.e., ca. retains 91% of its initial capacity (400 mAh g(-1)) after 100 cycles and delivers a high capacity of similar to 200 mAh g(-1) at a very high rate of 8 C (4000 mA g(-1)). The improvement in the electrochemical performance can be attributed to the triple layered structure in which the inner WC and outer graphene conductive buffer matrix not only can buffer the volume changes of the Sn thin-layer during cycling, but also ensure good electrical contact of the electro-active particles. Furthermore, a full cell coupled with spinel LiNi0.5Mn1.5O4 cathode in this paper demonstrates full utilization of the Sn anode and an expected energy density value of 530 Wh kg(-1), showing a prospect for practical lithium-ion battery applications. (C) 2013 Elsevier Ltd. All rights reserved.