Article pubs.acs.org/JPCC
NiSb−Al2O3−C Nanocomposite Anodes with Long Cycle Life for LiIon Batteries Eric Allcorn and Arumugam Manthiram* Electrochemical Energy Laboratory & Materials Science and Engineering Program, The University of Texas at Austin, Austin, Texas 78712 ABSTRACT: A NiSb−Al2O3−C nanocomposite alloy anode has been synthesized by high-energy mechanical milling, involving the mechanochemical reduction of Sb2O3 by metallic Al and Ni in the presence of acetylene black carbon. X-ray diffraction and X-ray photoelectron spectroscopy confirm the presence of crystalline NiSb and amorphous Al2O3 in the final nanocomposite. Transmission electron microscopy analysis shows the distribution of nanoscale crystalline NiSb particles in the matrix of Al2O3 and carbon. The presence of reinforcing Al2O3 and nanoscale active particles give this nanocomposite excellent cycle life with demonstrated capacity of 280 mAh g−1 to 1000 cycles. While the as-synthesized sample suffers from low coulombic efficiency of 55% in the first cycle and a large irreversible loss of roughly 350 mAh g−1, post-heat-treatment processes dramatically reduce the irreversible loss to 150 mAh g−1 with a coulombic efficiency of 73%. Combined with good rate capability and a tap density of 1.3 g cm−3, NiSb−Al2O3−C has significant potential as an alternative to graphite anodes in Li-ion batteries.
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INTRODUCTION Lithium-ion batteries, with high gravimetric and volumetric energy storage capacity, have contributed significantly to the advancement and proliferation of portable electronics over the past two decades. These attractive attributes and the success of their application in portable electronics have led to the desire to implement lithium-ion batteries into transportation (in the form of electric or hybrid-electric vehicles) and stationary storage applications. For this to happen though, advancements are needed to improve both the safety and storage capacity of the current battery systems. These advancements will be realized through the development of new and improved materials components for the next generation of lithium-ion batteries. One area that has received considerable focus is the replacement of the graphite anode currently used in most of the commercial lithium-ion batteries. As an anode, graphite has a relatively low theoretical capacity of 372 mAh g−1 because its intercalation reaction with lithium only allows the accommodation of one Li+ ion for every six C atoms (LiC6). Graphite also has a low tap density (
