Synthesis of porous-CoN nanoparticles and their application as a high capacity anode for lithium-ion batteries

Abstract

CoN nanoparticles are prepared by nitridation of Co 3O 4 in the presence of NH 3 + N 2 atmosphere and characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM) along with selective area electron diffraction (SAED) and BET surface area techniques. The Li-cycling performance of porous-CoN nanoparticles is evaluated by galvanostatic cycling and cyclic voltammetry (CV) in cells with Li-metal as the counter electrode in the voltage range of 0.005-3.0 V at ambient temperature. When cycled at 250 mA g -1 (0.31 C; 1C = 800 mA g -1), a first-cycle reversible capacity of 780 (±5) mA h g -1 (2.13 moles of Li) is noticed. During cycling, an increase in reversible capacity is observed from 710 (±5) mA h g -1 (1.93 moles of Li) at the 5 th cycle to 790 (±5) mA h g -1 (2.15 moles of Li) at the 25 th cycle. After this, capacity-fading is noticed and reaches 660 (±5) mA h g -1 (1.8 moles of Li) at the end of the 60 th cycle. The capacity-fading is 16% in the range of 25-60 cycles. Excellent rate capability is shown when the cell is cycled at 1.25 C (up to 60 cycles). The coloumbic efficiency is found to be >96% in the range of 10-60 cycles. From CV, the average charge and discharge potentials are; 2.2 and 0.87 V, respectively. The Li-cycling behavior of porous-CoN nanoparticles is discussed based on the observed capacity, ex situ XRD, HR-TEM and SAED data. The results show that porous-CoN nanoparticles are a prospective anode material for Li-ion batteries. © 2012 The Royal Society of Chemistry.