Confining invasion directions of Li+ to achieve efficient Si anode material for lithium-ion batteries

Tremendous volume expansion of silicon anode during cycling limits its further application. Here, a novel silicon nano-ribbon (SiNR) with (110) crystal plane is proposed as anode for the Lithium-ion batteries. The SiNRs with (110) crystal plane have been synthesized by a simple electrochemical micromachining method. Both invasion direction of the lithium-ions and expansion directions of the lithiated silicon are limited to the <110> crystal direction. Recrystallization of SiNR induced by the retention of silicon atomic chains after delithiation is verified experimentally and theoretically. Such SiNR, without necessary surface coating treatment, exhibits high ionic conductivity, high stable solid electrolyte interphase (SEI) and long cycling stability, retaining a specific capacity of 1721.3 mAh g−1 (∼80% capacity retention) after 2000 cycles with an initial coulombic efficiency (CE) of 83%. The rational design of nanostructured battery materials and electrodes in this work also opens a new dimension in material design for other batteries.