A Li-Ion Battery Using Nanostructured Sn@C Alloying Anode and High-Voltage LiNi0.35Cu0.1Mn1.45Al0.1O4 Spinel Cathode

Abstract

Nanostructured Sn@C anode is synthesized by carbon coating of nanosized tin for Li-ion battery. The Sn detected by X-ray diffraction (XRD) is quantified over 40 wt% by thermogravimetric analysis. Transmission and scanning electron microscopy (SEM) show a carbon matrix holding nanometric Sn operating from 0.8 to 0.01 V versus Li+/Li with low resistance, as indicated by cyclic voltammetry and electrochemical impedance spectroscopy. The Sn@C performs with initial capacity ranging from 630 mAh g−1 at 200 mA g−1 to 311 mAh g−1 at 1200 mA g−1 that decreases after 25 cycles and stabilizes to values from 403 to 268 mAh g−1, respectively. High-voltage LiNi0.35Cu0.1Mn1.45Al0.1O4 cathode is achieved by coprecipitation and high-temperature treatment. XRD and SEM demonstrate the crystalline structure of the disordered spinel without impurities and homogeneous submicron morphology. Cu and Al substitution for Ni and Mn leads to excellent reversibility and low impedance, with electrochemical process evolving between 4.7 and 4.8 V versus Li+/Li. The cathode reveals a capacity of ≈110 mAh g−1 retained for 88% after 100 cycles at 0.6C rate. Sn@C and LiNi0.35Cu0.1Mn1.45Al0.1O4 are combined in a new Li-ion cell delivering 110 mAh g−1 at 4.2 V with practical energy of 165 Wh kg−1.