Nasim Amiralian

Easily deconstructed, high aspect ratio cellulose nanofibres from Triodia pungens; an abundant grass of Australia's arid zone

The production of high aspect ratio cellulose nanofibres without resorting to very harsh mechanical and/or chemical processing steps remains a challenge that hinders progress in the fast-moving nanocellulose field. In response to this challenge, herein we report the preparation of high aspect ratio (>500) and small diameter (<8 nm) cellulose nanofibrils through the deconstruction of Australian native ‘spinifex’ grass (Triodia pungens) by applying very mild pulping conditions combined with only one pass of high pressure homogenization. Spinifex grass has an unusually high hemicellulose content, which facilitates this easy fibrillation process. Tensile measurements of the nanopaper produced by vacuum filtration indicated a high toughness of about 12 MJ m−3, a tensile strength of 82 MPa and a high elongation at break of 18%. The transverse elastic modulus of single nanofibrils analysed by AM-FM is in the range of 19–24 GPa. Under these mild processing conditions, Triodia pungens nanofibrils retained their crystallinity.

Spinifex nanocellulose derived hard carbon anodes for high-performance sodium-ion batteries

The selection of an appropriate anode material is a critical factor in dictating the effectiveness of sodium-ion batteries as a cost-effect alternative to lithium-ion batteries. Hard carbon materials sourced from biomass offer the potential for a more sustainable anode material, while also addressing some of the thermodynamic issues associated with using traditional graphite anodes for sodium-ion batteries (NIBs). Herein, we report the preparation of carbon electrode materials from low-cost cellulose nanofibers derived from an Australian native arid grass ‘spinifex’ (Triodia pungens). This nanocellulose derived carbon produced by a fast, low temperature carbonization protocol showed superior performance as an anode for NIBs with a specific capacity (386 mA h g−1 at 20 mA g−1) on par with that of the graphite based anode for lithium-ion batteries, and is one of the highest capacity carbon anodes reported for NIBs. The excellent electrochemical performance is attributed to the large interlayer spacing of the carbon (∼0.39 nm). Superior cycling stability and high rate tolerance (326 mA h g−1 at 50 mA g−1 and 300 mA h g−1 at 100 mA g−1) suggest that hard carbons derived from sustainable precursors are promising for next generation rechargeable batteries.

Nanotechnology and the Dreamtime knowledge of spinifex grass

This paper is premised on several Australian Aboriginal myths (or sacred histories) from the Georgina River Basin region of Central Australia that concern the Triodia grasses known locally as spinifex (or aywerte). These sacred histories provide an epistemological foundation to the regional intellectual property over traditional spinifex technologies formerly utilized for architectural, material and medicinal functions. Aboriginal uses of spinifex were once widespread but declined in the latter 20th century, and ethno-scientific knowledge has severely diminished. The dominant uses of spinifex in Aboriginal culture were as waterproof roof-thatching material and as a gum for adhesive functions. The chapter explores the contemporary revitalization of this knowledge in collaborative research partnership between a group of traditional tribal owners (the Indjalandji, Alyawarr, Wakaya, and Bularnu peoples) and a team of scientific researchers from the University of Queensland lead by the authors and including nano-biomaterial engineers. The partnership involves engaging with, and resolving an interface between, the respective epistemologies and work cultures of the university researchers and our Aboriginal partners.