Interconnected stacked hollow carbon spheres uniformly embedded with Ni2P nanoparticles as scalable host for practical Li metal anode

Abstract

Porous carbon is a promising host for stable lithium (Li) metal composite anodes. However, homogeneous lithiophilicity modification and large-scale production of these material are difficult to address simultaneously, leading to poor electrochemical performance and limiting practical application of Li metal anode. Herein, we display a large-scale productive three-dimensional (3D) interconnected stacked hollow carbon spheres modified with evenly dispersed Ni2P nanoparticles (Ni2P@ISHCP). Interestingly, the interconnected hollow carbon skeletons are further graphitized during the simple and scalable preparation process of Ni2P nanoparticles, which is favorable for the higher ion/electron conductivity. Impressively, density functional theory calculations (DFT) demonstrate Li+ adsorbs Ni2P nanoparticle presenting the stronger binding energy and a mass of charge transfer compared with pure carbon. It benefits a lower nucleation overpotential and the homogeneous Li selective deposition into the 3D interconnected hollow spheres. As expected, a superior average Coulombic efficiency (CE) of 98.4% near 400 cycles at 1 mA cm−2 and a long cycling life over 1000 h cycling with a low overpotential of 12 mV are successfully achieved. Coupled with a LiFePO4 cathode, the fabricated full-cell exhibits a capacity retention of 99.3% with 135 mAh g−1 over 200 cycles at 1C and outstanding rate capability, presenting the tremendous practical application potential.