Holey two-dimensional transition metal oxide nanosheets for efficient energy storage

Lele Peng,Khalil Amine,Guihua Yu,Pan Xiong,Jun Lu,Dahong Chen,Yifei Yuan,Yue Zhu,Xiangyi Luo,Lu Ma

doi:10.1038/ncomms15139

Abstract

Transition metal oxide nanomaterials are promising electrodes for alkali-ion batteries owing to their distinct reaction mechanism, abundant active sites and shortened ion diffusion distance. However, detailed conversion reaction processes in terms of the oxidation state evolution and chemical/mechanical stability of the electrodes are still poorly understood. Herein we explore a general synthetic strategy for versatile synthesis of various holey transition metal oxide nanosheets with adjustable hole sizes that enable greatly enhanced alkali-ion storage properties. We employ in-situ transmission electron microscopy and operando X-ray absorption structures to study the mechanical properties, morphology evolution and oxidation state changes during electrochemical processes. We find that these holey oxide nanosheets exhibit strong mechanical stability inherited from graphene oxide, displaying minimal structural changes during lithiation/delithiation processes. These holey oxide nanosheets represent a promising material platform for in-situ probing the electrochemical processes, and could open up opportunities in many energy storage and conversion systems.

Highlights

Transition metal oxide nanomaterials are promising electrodes for alkali-ion batteries owing to their distinct reaction mechanism, abundant active sites and shortened ion diffusion distance
graphene oxide (GO) was first employed as a template to grow various TMO precursors on its surfaces, followed by post-thermal treatment to transform TMO precursors to 2D holey TMO nanosheets owing to the synergistic effects of chemical interconnection of TMO nanoparticles and controlled decomposition of GOs
TMO precursor/rGO composites were firstly prepared via solutionphase reaction between transition metal ions and GO, which was partially reduced to reduced graphene oxide[37,38]

Summary

Introduction

Transition metal oxide nanomaterials are promising electrodes for alkali-ion batteries owing to their distinct reaction mechanism, abundant active sites and shortened ion diffusion distance. We employ in-situ transmission electron microscopy and operando X-ray absorption structures to study the mechanical properties, morphology evolution and oxidation state changes during electrochemical processes. We find that these holey oxide nanosheets exhibit strong mechanical stability inherited from graphene oxide, displaying minimal structural changes during lithiation/delithiation processes. There is a great amount of research on simple and mixed transition metal oxides as lithium ion battery and sodium ion battery anodes[33,34,35,36], but detailed conversion reaction process in terms of the oxidation state changes (chemical stability) and morphology evolution (mechanical stability) are still relatively poorly understood. 2D holey TMO nanosheets exhibit much improved rate capability and cycling stability for both lithium and sodium ion storage, due to the increased surface areas and interfaces, and facile interfacial a GO

Methods

Results

Conclusion