  Extensive efforts have been devoted to C-Si compound materials for improving
the limited specific capacity of graphite anode and avoiding the huge volume
change of Si anode in Li-ion battery, but not much progress has been made
during the past decades. Here, for the first time we apply the targeted
structure search by using Li in desired quantity as chemical template to
regulate the bonding between C and Si, which makes searching more feasible for
us to find a new stable phase of C2Si (labelled as T-C2Si) that can better fit
the XRD data of silicon dicarbide synthesized before. Different from the
conventional semiconducting silicon carbides, T-C2Si is not only metallic with
high intrinsic conductivity for electrons transport, but also porous with
regularly distributed channels in suitable size for Li ions experiencing a low
energy barrier. T-C2Si exhibits a high specific capacity of 515 mA/g, a high
average open-circuit voltage of 1.14 eV, and a low volume change of 1.6%. These
parameters meet the requirements of an ideal anode material with high
performance for electric vehicles. Moreover, our targeted search strategy
guarantees the resulting anode material with a desirable specific capacity and
a small volume change during charging /discharging, and it can be used to find
new geometric configurations for other materials.
