High energy lithium ion battery electrode materials; enhanced charge storage via both alloying and insertion processes

Mechthild Lübke,Dougal Howard,Ceilidh F Armer,Aleksandra J Gardecka,Adrian Lowe,M.V Reddy,Zhaolin Liu,Jawwad A Darr

doi:10.1016/j.electacta.2017.02.063

Abstract

A series of nano-sized tin-doped metal oxides of titanium(IV), niobium(V) and vanadium(IV), were directly synthesized using a continuous hydrothermal process and used for further testing without any post-treatments. Each of the as-prepared powders was characterized via a range of analytical techniques including powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Brunauer-Emmett-Teller surface area measurements, as well as being investigated as an electrode material in a lithium-ion coin cell (vs lithium metal). All the tin-doped nanomaterials showed higher specific capacities compared to their undoped metal oxide counterparts. The increased charge storage was discussed to originate from the electrochemical activation of the tin dopant as an alloying material. Overall, this work presents a reliable method of combining stable insertion materials with high capacity tin alloying materials under scaled-up conditions.

Highlights

Rechargeable lithium-ion batteries represent the dominant energy storage technology in a range of portable devices from smartphones and laptops to cordless power tools
The yield was low for the vanadium dioxide synthesis as it was not optimized in this first attempt and can be increased in the future by the use of an appropriate base or an alternative precursor that is less soluble [38]
Ti0.88Sn0.12O2, Nb1.63Sn0.34O5 and V0.8Sn0.2O2 were synthesized in a single step via a pilot scale continuous hydrothermal flow synthesis (CHFS) hydrothermal reactor at a production rate of at least 65 g hÀ1

Summary

Introduction

Rechargeable lithium-ion batteries represent the dominant energy storage technology in a range of portable devices from smartphones and laptops to cordless power tools. High capacity and low operating potential (vs Li/Li+) electrode materials, are desirable for the negative electrode of a lithium-ion battery [2]. There are numerous candidate negative electrode materials in lithium-ion batteries that can be classified as storing charge predominately via insertion/intercalation, pseudocapacitive surface reactions, conversion or alloying processes [3]. TiO2, Nb2O5 and VO2 have attracted attention as lithium-ion battery negative electrodes, due to their relatively low cost and reasonably high theoretical capacities of 175, 200 and 320 mAh gÀ1, respectively [4,5,6,7,8]

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