Synergic effect of decoration of Nickel Oxide nanoparticles on Silicon for enhanced electrochemical performance in LIBs

An utmost effort is continued for the architecture of anode materials with high specific capacity and long cycling stability for lithium-ion batteries (LIBs). In this context, silicon has been preferred due to its high capacity though it has been suffered by excessive volume expansion during electrochemical reactions as well as poor cyclability due to reduction in conductivity. Hence hybridization of silicon with apt materials could be the significant approach to overcome the above problems. Therefore, demonstrated uniform decoration of nickel oxide (NiO) nanoparticles (15-20nm) on silicon nanosheets using Bis(cyclopentadienyl) nickel(II) (C10H10Ni) at low temperature taking advantage of presence of two unpaired electron in an antibonding orbital in cyclopentadienyl group. The formation and growth mechanism has been discussed in detail. The electrochemical study of nanocomposite exhibits an initial delithiation capacity, 2507mAhg−1 with reversible capacity 2162 mAhg−1 having 86% retention and better cycling stability up to 500 cycles. At optimum concentration, NiO nanoparticles facilitate the Li ion adsorptions which in turn accelerate the transport of Li+ ions to active sites of silicon. Warburg coefficient and Li ion diffusion of electrodes confirms the enhancement in charge transfer process at the electrode/electrolyte interface with NiO nanoparticles. Further, the NiO nanoparticles with a uniform distribution suppress the agglomeration of Si nanosheets and provide sufficient space to accommodate a volume change of Si during cycling which also reduces diffusion length path of the Li ions. It also helps to strengthen mechanical stability which might be helping to prevent cracking of silicon due to volume expansion and maintains the Li ion transport pathway of the active material, resulting in enhanced cycling stability. Due to the synergic effect between NiO nanoparticles and Si sheet, nanocomposite delivers high reversible capacity.