Carbon aerogels from bacterial nanocellulose as anodes for lithium ion batteries

Liping Wang,German Salazar-Alvarez,Christina Schütz,Maria-Magdalena Titirici

doi:10.1039/c3ra47853j

Abstract

Carbon aerogels with large open pores and high surface area are fabricated via pyrolysis of a readily available natural resource, e.g., bacterial nanocellulose (BNC) aerogels. Freeze-drying of the BNC hydrogels is used to preserve the 3D open network structure upon calcination whereas using Fe(III) improves the yield and H/C ratio. These carbon aerogels are explored as anodes in lithium ion batteries where it is shown that they deliver superior capacity retention and rate performance compared to other carbon-based materials.

Highlights

The search for alternative energy sources to fossil fuels has increased in the recent years due to growing environmental concerns and an increasing oil price
We study the behaviour of a carbon aerogel network obtained through the pyrolysis of bacterial nanocellulose (BNC) aerogels as anode material in lithium ion batteries (LIBs)
Photograph of a freeze-dried bacterial nanocellulose aerogel (FDBNC), (b and c) SEM images of FD-BNC aerogels at different magnifications, (d) photograph of a carbon aerogel obtained through pyrolysis of freeze-dried bacterial nanocellulose at 900 C (FD-BNC900), (e and f) SEM micrograph of FD-BNC-900 aerogels at different magnifications

Summary

Introduction

The search for alternative energy sources to fossil fuels has increased in the recent years due to growing environmental concerns and an increasing oil price. We study the behaviour of a carbon aerogel network obtained through the pyrolysis of BNC aerogels as anode material in LIBs. The pyrolyzed bres show a disordered structure with an enhanced surface area, resulting in anode materials with a good rate performance and capacity retention. The capacity of the carbon aerogel as electrode is considerably better than that obtained for carbonized lms produced from BNC, which was reported to be just about 100 mA h gÀ1.35 The cellulose-derived carbon shows a superior rate performance (Fig. 2c). It has been suggested that such relatively disordered structures may result in a decreased capacity,[4,39] these misaligned regions may be the origin of the increased surface area and higher rate performance.[4].

Pyrolysis of BNC

Characterisation

Electrochemical test