A highly-deformable composite composed of an entangled network of electrically-conductive carbon-nanotubes embedded in elastic polyurethane

Advances in lithium ion batteries would facilitate technological developments inareas from electrical vehicles to mobile communications. While 2-dimensional systems like MoS2 are promising electrode materials due to their potentially high capacity, their poor ratecapability and low cycle-stability are severe handicaps. Here we study the electrical, mechanical and lithium storage properties of solution-processed MoS2/carbon nanotube anodes.Nanotube addition gives up to ×10 10 and ×40 increases in electrical conductivity and mechanical toughness respectively. The increased conductivity results in up to a ×100 capacity enhancement to ~1200 mAh/g (~3000 mAh/cm 3 ) at 0.1 A/g, while the improved toughness significantly boosts cycle stability. Composites with 20 wt% nanotubes combined high reversible capacity with excellent cycling stability (e.g. ~950 mAh/g after 500 cycles at 2 A/g) and high-rate capability (~600 mAh/g at 20 A/g). The conductivity, toughness and capacity scaled with nanotube content according to percolation theory while the stability increased sharply at the mechanical percolation threshold. We believe the improvements in conductivity and toughness obtained after addition of nanotubes can be transferred to other electrode materials such as silicon nanoparticles.Keywords: percolating, network, anode, mechanical 2 In recent years, lithium ion batteries (LIBs) have become the most common rechargeable power sources for portable electronic devices and electric vehicles. 1, 2 Nevertheless, they still suffer from several problems; their energy and especially power densities have not fulfilled their ultimate potential while their safety record is not unblemished. 3 A significant problem is that graphite, the dominant anode material used in LIBs, is limited by a relatively low theoretical capacity of 372 mAh/g. 4 As such, the development of the next-generation of LIBs, is expected to see the replacement of graphite-based anodes with alternative materials having higher capacity at similarly low cost. While a range of materials, including silicon, have been envisaged as future LIB anode materials, 4 of particular interest are 2-dimensional (2D) nanomaterials 5 such as graphene 6 and MoS2. 7 Over the last decade, 2D nano-materials have generated much excitement in the nanomaterials science community. [8][9][10] They come in many types including graphene, transition metal dichalcogenides (TMDs) and transition metal oxides (TMOs). These materials consist of covalently bonded monolayers which can stack via van der Waals interactions to form layered crystals. 8,9 Such 2D nanomaterials are often found as nanosheets with lateral size ranging from 10s of nm to microns and thickness of ~nm. 9 These materials have shown potential for applications 5 in both energy generation 11 and storage. 12 In the context of LIBs, exfoliated TMDs have received significant attention as prospective anode materials. 13,14 While bulk MoS2 was proposed 15 as a Li ion battery electrode material as early as 1980 due to its hi...

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“…48 In addition, we expect nanotubes to provide more effective reinforcement because of their ability to form entangled networks. 49 …”

Section: Mos2-only Anodesmentioning

confidence: 99%

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS₂/Nanotube Composite Lithium Ion Battery Electrodes

et al. 2016

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“…The published data show that the electrical response to strain or stress is sufficient and the sensing can be performed in real time [2,3,[10][11][12][13].…”

Section: A Compression Detectionmentioning

confidence: 99%

“…Moreover, the resistance of the maximally elongated composite returns in the unloaded state to the residual value 1750 Ω ( 0 R R  =10.29) which differs from the initial resistance value of 170 Ω. The residual strain of the composite in the unloaded state is 24.7 % due to the composite irreversible deformation in the first highly deforming cycle [3]. The gauge factor for the elongating composite can be calculated using data from Fig.…”

Section: Sensing Of Tensile Deformationmentioning

confidence: 99%

“…A pedaling frequency about 1 Hz resulted more than 1000 cycles during which the composite resistance changes were repetitive and no material property variation is observed. Though a commercial sensor made from MWCNT network/PU composite should withstand multiples of test cycles, we believe that the composite has reasonable durability and reversibility of the base characteristics for practical application [3].…”

Section: Sensing Of Tensile Deformationmentioning

confidence: 99%

“…The copper has a GF of about 2.5, the metal sheet strain gauges have values of GF 2-5, GF of the pure MWCNT network (buckypaper) was experimentally determined as 0.34 [1], or 7 [2] at small strain about 0.1 % due to the weak van der Waals attraction between nanotubes. GF of stretchable composite consisting of multi-walled carbon nanotubes network/polyurethane (MWCNT/PU) stretched up to 400 % and GF was found to be nearly 69 at this strain [3].…”

Section: Introductionmentioning

confidence: 99%

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A Flexible Multifunctional Sensor Based on Carbon Nanotube/Polyurethane Composite

et al. 2013

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Piezoresistivity, Strain, and Damage Self‐Sensing of Polymer Composites Filled with Carbon Nanostructures

2018

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Previous and current research on piezoresistivity of polymer composites filled with carbon nanostructures is reviewed. The review covers the use of the coupled electro‐mechanical response of these materials to self‐sense their strain and damage during mechanical loading. The mechanisms yielding changes in electrical resistance upon mechanical loading in polymer composites filled with carbon nanostructures are first discussed. Published knowledge is then summarized, starting with framework literature on carbon black and graphite and then moving to more recent research on carbon nanotubes, exfoliated graphite, and few‐layer graphene sheets. Piezoresistive studies of polymer nanocomposites with aligned carbon fillers are also reviewed. It is aimed that this review contributes in collecting, organizing, and summarizing the knowledge, foundations, and state of the art on the piezoresistive response of polymer composites filled with different carbon allotropes, providing new perspectives and advancing towards the fast development of smart self‐sensing carbon filled nanocomposites.

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A highly-deformable composite composed of an entangled network of electrically-conductive carbon-nanotubes embedded in elastic polyurethane

Cited by 99 publications

References 20 publications

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS₂/Nanotube Composite Lithium Ion Battery Electrodes

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS₂/Nanotube Composite Lithium Ion Battery Electrodes

A Flexible Multifunctional Sensor Based on Carbon Nanotube/Polyurethane Composite

Piezoresistivity, Strain, and Damage Self‐Sensing of Polymer Composites Filled with Carbon Nanostructures

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A highly-deformable composite composed of an entangled network of electrically-conductive carbon-nanotubes embedded in elastic polyurethane

Cited by 99 publications

References 20 publications

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS2/Nanotube Composite Lithium Ion Battery Electrodes

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS2/Nanotube Composite Lithium Ion Battery Electrodes

A Flexible Multifunctional Sensor Based on Carbon Nanotube/Polyurethane Composite

Piezoresistivity, Strain, and Damage Self‐Sensing of Polymer Composites Filled with Carbon Nanostructures

Contact Info

Product

Resources

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Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS₂/Nanotube Composite Lithium Ion Battery Electrodes

Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS₂/Nanotube Composite Lithium Ion Battery Electrodes