Carbon-Coated Honeycomb Ni-Mn-Co-O Inverse Opal: A High Capacity Ternary Transition Metal Oxide Anode for Li-ion Batteries

David Mcnulty,Hugh Geaney,Colm O'Dwyer

doi:10.1038/srep42263

Abstract

We present the formation of a carbon-coated honeycomb ternary Ni-Mn-Co-O inverse opal as a conversion mode anode material for Li-ion battery applications. In order to obtain high capacity via conversion mode reactions, a single phase crystalline honeycombed IO structure of Ni-Mn-Co-O material was first formed. This Ni-Mn-Co-O IO converts via reversible redox reactions and Li2O formation to a 3D structured matrix assembly of nanoparticles of three (MnO, CoO and NiO) oxides, that facilitates efficient reactions with Li. A carbon coating maintains the structure without clogging the open-worked IO pore morphology for electrolyte penetration and mass transport of products during cycling. The highly porous IO was compared in a Li-ion half-cell to nanoparticles of the same material and showed significant improvement in specific capacity and capacity retention. Further optimization of the system was investigated by incorporating a vinylene carbonate additive into the electrolyte solution which boosted performance, offering promising high-rate performance and good capacity retention over extended cycling. The analysis confirms the possibility of creating a ternary transition metal oxide material with binder free accessible open-worked structure to allow three conversion mode oxides to efficiently cycle as an anode material for Li-ion battery applications.

Highlights

Three dimensional (3D) materials such as inverse opals (IOs) are very attractive architectures for the active materials of Li-ion batteries[21]
Converting an initial single phase mixed ternary metal oxide (TMO) compound to an interconnected triple unary oxide phase system via lithiation ensures that the 3D porous networked material can be engineered as a monolithic single open structure, rather than a composite consisting of a mixture of unary metal oxides, which tend to agglomerate as individual random mixtures of particles
Polystyrene sphere (PS) templates were infilled with an Ni-Mn-Co-O precursor solution and annealed at 450 °C in air to crystallize the Ni-Mn-Co-O sample and to remove the sphere template

Summary

Introduction

Three dimensional (3D) materials such as inverse opals (IOs) are very attractive architectures for the active materials of Li-ion batteries[21]. The anodic peak at ~1.06 V was present at the same potential for Ni-Mn-Co-O NPs and all IO samples, and may be associated with the decomposition of Li2O formed during the initial cathodic scan.

Results

Conclusion