miun.sePublikasjoner
Endre søk
Link to record
Permanent link

Direct link
BETA
Publikasjoner (10 av 18) Visa alla publikasjoner
Blomquist, N., Alimadadi, M., Hummelgård, M., Dahlström, C., Olsen, M. & Olin, H. (2019). Effects of Geometry on Large-scale Tube-shear Exfoliation of Multilayer Graphene and Nanographite in Water. Scientific Reports, 9(1), Article ID 8966.
Åpne denne publikasjonen i ny fane eller vindu >>Effects of Geometry on Large-scale Tube-shear Exfoliation of Multilayer Graphene and Nanographite in Water
Vise andre…
2019 (engelsk)Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, nr 1, artikkel-id 8966Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Industrially scalable methods for the production of graphene and other nanographites are needed to achieve cost-efficient commercial products. At present, there are several available routes for the production of these materials but few allow large-scale manufacturing and environmentally friendly low-cost solvents are rarely used. We have previously demonstrated a scalable and low-cost industrial route to produce nanographites by tube-shearing in water suspensions. However, for a deeper understanding of the exfoliation mechanism, how and where the actual exfoliation occurs must be known. This study investigates the effect of shear zone geometry, straight and helical coil tubes, on this system based on both numerical simulation and experimental data. The results show that the helical coil tube achieves a more efficient exfoliation with smaller and thinner flakes than the straight version. Furthermore, only the local wall shear stress in the turbulent flow is sufficient for exfoliation since the laminar flow contribution is well below the needed range, indicating that exfoliation occurs at the tube walls. This explains the exfoliation mechanism of water-based tube-shear exfoliation, which is needed to achieve scaling to industrial levels of few-layer graphene with known and consequent quality.

HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-36084 (URN)10.1038/s41598-019-45133-y (DOI)000472137700062 ()2-s2.0-85067662886 (Scopus ID)
Tilgjengelig fra: 2019-05-06 Laget: 2019-05-06 Sist oppdatert: 2019-10-16bibliografisk kontrollert
Blomquist, N. (2019). Large-Scale Graphene Production for Environmentally Friendly and Low-Cost Energy Storage: Production, Coating, and Applications. (Doctoral dissertation). Sundsvall: Mid Sweden University
Åpne denne publikasjonen i ny fane eller vindu >>Large-Scale Graphene Production for Environmentally Friendly and Low-Cost Energy Storage: Production, Coating, and Applications
2019 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

There is great demand for energy-efficient, environmentally sustainable, and cost-effective electrical energy storage devices. One important aspect of this demand is the need for automotive electrification to achieve more energy-efficient transportation at a reasonable cost, thus supporting a fossil-fuel free society. Another important aspect is the requirement for energy storage in the growing field of renewable energy production from wind and solar sources, which generates an irregular supply of electricity due to weather conditions.Much of the research in this area has been conducted in the field of battery technology with impressive results, but the need for rapid storage devices such as supercapacitors is growing. Due to the excellent ability of supercapacitors to handle short peak power pulses with high efficiency along with their long lifetime and superior cyclability, their implementations range from small consumer electronics to electric vehicles and stationary grid applications. Supercapacitors also have the potential to complement batteries to improve pulse efficiency and lifetime of the system, however, the cost of supercapacitors is a significant issue for large-scale commercial use, leading to a demand for sustainable, low-cost materials and simplified manufacturing processes. An important way to address this need is to develop a cost-efficient and environment-friendly large-scale process to produce highly conductive nanographites, such as graphene and graphite nanoplatelets, along with methods to manufacture low-cost electrodes from large area coating.

In this thesis, I present a novel process to mechanically exfoliate industrial quantities of nanographite from graphite in an aqueous environment with low energy consumption and at controlled shear conditions. The process is based on hydrodynamic tube-shearing and can produce both multilayer graphene and nanometer-thick and micrometer-wide flakes of nanographite. I also describe the production of highly conductive and robust carbon composites based on the addition of nanocellulose during production; these are suitable as electrodes in applications ranging from supercapacitors and batteries to printed electronics and solar cells.Furthermore I demonstrate a scalable route for roll-to-roll coating of the nanographite-nanocellulose electrode material and propose a novel aqueous, low-cost, and metal-free supercapacitor concept with graphite foil functioning as the current collector. The supercapacitors possessedmore than half the specific capacitance of commercial units but achieved a material cost reduction of more than 90 %, demonstrating anenvironment-friendly, low-cost alternative to conventional supercapacitors.

Abstract [sv]

Det finns en stor efterfrågan av energieffektiva, miljömässigt hållbara och kostnadseffektiva elektriska energilagringsenheter. En viktig del av denna efterfrågan kommer från fordonsindustrins behov av elektrifiering, för att uppnå mer energieffektiva fordon till en rimlig kostnad och på så vis bidra till ett fossilfritt samhälle. En annan viktig del är behovet av energilagring för den ökande andelen förnybar energiproduktion från sol- och vindkraft, som genererar elektrisk energi oregelbundet utifrån gällande väderförhållanden. Det pågår mycket forskning inom området för batteriteknik och framgångarna är imponerande men behovet växer också snabbt för snabba energilagrare som exempelvis superkondensatorer. Tack vare superkondensatorernas utmärkta prestanda, när det gäller att hantera korta effektpulser med hög effektivitet tillsammans med dess långa livslängd och överlägsna cyklingsbarhet, sträcker sig applikationerna frånhemelektronik till elfordon och elnätsapplikationer. Superkondensatorer har också potential att komplettera batterier för att uppnå energilagringssystem med ökad pulseffiktivitet och livslängd. Nackdelen är superkondensatorns kostnad, som markant hämmar storskaligkommersialisering, och således kräver utveckling av hållbara och kostnadseffektiva material tillsammans med förenklade tillverkningsmetoder. Ett sätt att lösa detta på, är att utveckla en kostnadseffektiv och miljövänlig process i stor skala för att framställa nanografit med hög elektrisk ledningsförmåga, så som grafén och grafitnanoflak.

I denna avhandling presenterar jag en ny process för att mekaniskt exfoliera grafit till nanografit storskaligt i vattendispersion, med en låg energiåtgång och under kontrollerade skjuvförhållanden. Processen är baserad på hydrodynamisk skjuvning i rör och denproducerar grafen samt nanometertunna och mikrometerbreda flak av nanografit. Som tillägg visar jag också hur robusta kompositer kan tillverkas med hög ledningsförmåga genom att tillsätta nanofibrillerad cellulosa under processen. Dessa kompositer är lämpliga som elektroder i applikationer från superkondensatorer och batterier till tryckt elektronik och solceller.Jag demonstrerar också en skalbar metod för rulle-till-rulle bestrykning av nanografit-nanocellulosa-materialet samt föreslår ett nytt lågkostnads-koncept för metall-fria superkondensatorer med vattenbaserad elektrolyt, där vi använt grafitfolie som kontakt. Superkondensatorerna hade mer än halva den specifika kapacitansen jämfört med kommersiella enheter men materialkostnaden var 90 % lägre, vilket visar på ett miljövänligt lågkostnadsalternativ till konventionella superkondensatorer.

sted, utgiver, år, opplag, sider
Sundsvall: Mid Sweden University, 2019. s. 90
Serie
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 297
Emneord
Graphene, Energy storage, Supercapacitors, EDLC
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-36068 (URN)978-91-88527-99-8 (ISBN)
Disputas
2019-05-10, O102, Holmgatan 10, Sundsvall, 10:15 (engelsk)
Opponent
Veileder
Merknad

Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 3 (inskickat), delarbete 5 (manuskript).

At the time of the doctoral defence the following papers were unpublished: paper 3 (submitted), paper 5 (manuscript).

Tilgjengelig fra: 2019-05-06 Laget: 2019-05-02 Sist oppdatert: 2019-05-06bibliografisk kontrollert
Zhang, R., Hummelgård, M., Örtegren, J., Yang, Y., Andersson, H., Balliu, E., . . . Olin, H. (2019). Sensing body motions based on charges generated on the body. Nano Energy, 63, Article ID 103842.
Åpne denne publikasjonen i ny fane eller vindu >>Sensing body motions based on charges generated on the body
Vise andre…
2019 (engelsk)Inngår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 63, artikkel-id 103842Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The sensing of body motions is of great importance in areas such as healthcare, rehabilitation, and human-computer interactions. Different methods have been developed based on visual or electrical signals. However, such signals are acquired by external devices and are not intrinsic signals that are created on the body. Here, we report a new universal body motion sensor (UBS) to detect motions based on the intrinsic contact electrification (CE) of the skin or electrical induction (EI) of the body. The CE or EI generates charges on the body, leading to potential differences between the body and ground that can be measured to identify different body motions, such as motions of the head, arms, fingers, waist, legs, feet and toes. Proof-of-concept experiments have demonstrated that the UBS can be used to monitor the conditions of people with Parkinson's disease (PD) and to quantitatively monitor the recovery of those with a leg injury, suggesting great potential for healthcare applications.

Emneord
Body motions, Sensors, Charges, Contact electrification, Electrical induction, Healthcare
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-36826 (URN)10.1016/j.nanoen.2019.06.038 (DOI)000480422400034 ()2-s2.0-85068234493 (Scopus ID)
Tilgjengelig fra: 2019-08-12 Laget: 2019-08-12 Sist oppdatert: 2019-10-16bibliografisk kontrollert
Phadatare, M. R., Patil, R., Blomquist, N., Forsberg, S., Örtegren, J., Hummelgård, M., . . . Olin, H. (2019). Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries. Scientific Reports, 9, Article ID 14621.
Åpne denne publikasjonen i ny fane eller vindu >>Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries
Vise andre…
2019 (engelsk)Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikkel-id 14621Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.

Emneord
Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries Supplementary Information
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-37569 (URN)10.1038/s41598-019-51087-y (DOI)000489555900015 ()2-s2.0-85073112106 (Scopus ID)
Tilgjengelig fra: 2019-10-24 Laget: 2019-10-24 Sist oppdatert: 2019-11-14bibliografisk kontrollert
Rastabi, S. A., Mamoory, R. S., Dabir, F., Blomquist, N., Phadatare, M. R. & Olin, H. (2019). Synthesis of NiMoO4/3D-rGO Nanocomposite in Alkaline Environments for Supercapacitor Electrodes. Crystals, 9(1), Article ID 31.
Åpne denne publikasjonen i ny fane eller vindu >>Synthesis of NiMoO4/3D-rGO Nanocomposite in Alkaline Environments for Supercapacitor Electrodes
Vise andre…
2019 (engelsk)Inngår i: Crystals, ISSN 2073-4352, Vol. 9, nr 1, artikkel-id 31Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Although Graphene oxide (GO)-based materials is known as a favorable candidate for supercapacitors, its conductivity needs to be increased. Therefore, this study aimed to investigate the performance of GO-based supercapicitor with new methods. In this work, an ammonia solution has been used to remove the oxygen functional groups of GO. In addition, a facile precipitation method was performed to synthesis a NiMoO4/3D-rGO electrode with purpose of using synergistic effects of rGO conductivity properties as well as NiMoO4 pseudocapacitive behavior. The phase structure, chemical bands and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), Raman spectroscopy, and field emission secondary electron microscopy (FE-SEM). The electrochemical results showed that the NiMoO4/3D-rGO(II) electrode, where ammonia has been used during the synthesis, has a capacitive performance of 932 Fg(-1). This is higher capacitance than NiMoO4/3D-rGO(I) without using ammonia. Furthermore, the NiMoO4/3D-rGO(II) electrode exhibited a power density of up to 17.5 kW kg(-1) and an energy density of 32.36 Wh kg(-1). These results showed that ammonia addition has increased the conductivity of rGO sheets, and thus it can be suggested as a new technique to improve the capacitance.

Emneord
renewable energy systems, pseudocapacitive behavior, electrochemical results, ammonia, oxygen groups
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-35806 (URN)10.3390/cryst9010031 (DOI)000458578100031 ()
Tilgjengelig fra: 2019-03-19 Laget: 2019-03-19 Sist oppdatert: 2019-03-19bibliografisk kontrollert
Zhang, R., Hummelgård, M., Olin, H., Blomquist, N. & Andres, B. (2019). The application of papers in energy harvesting and storage. In: : . Paper presented at 2019 China International Specialty Papers Expo & Conference, Quzhou, China, October 16-18, 2019.
Åpne denne publikasjonen i ny fane eller vindu >>The application of papers in energy harvesting and storage
Vise andre…
2019 (engelsk)Konferansepaper, Oral presentation with published abstract (Fagfellevurdert)
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-37824 (URN)
Konferanse
2019 China International Specialty Papers Expo & Conference, Quzhou, China, October 16-18, 2019
Tilgjengelig fra: 2019-11-28 Laget: 2019-11-28 Sist oppdatert: 2019-12-13bibliografisk kontrollert
Andres, B., Dahlström, C., Blomquist, N., Norgren, M. & Olin, H. (2018). Cellulose binders for electric double-layer capacitor electrodes: The influence of cellulose quality on electrical properties. Materials & design, 141, 342-349
Åpne denne publikasjonen i ny fane eller vindu >>Cellulose binders for electric double-layer capacitor electrodes: The influence of cellulose quality on electrical properties
Vise andre…
2018 (engelsk)Inngår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 141, s. 342-349Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Cellulose derivatives are widely used as binders and dispersing agents in different applications. Binders composed of cellulose are an environmentally friendly alternative to oil-based polymer binding agents. Previously, we reported the use of cellulose nanofibers (CNFs) as binders in electrodes for electric double-layer capacitors (EDLCs). In addition to good mechanical stability, we demonstrated that CNFs enhanced the electrical performance of the electrodes. However, cellulose fibers can cover a broad range of length scales, and the quality requirements from an electrode perspective have not been thoroughly investigated. To evaluate the influence of fiber quality on electrode properties, we tested seven samples with different fiber dimensions that are based on the same kraft pulp. To capture the length scale from fibers to nanofibrils, we evaluated the performance of the untreated kraft pulp, refined fibers, microfibrillated cellulose (MFC) and CNFs. Electrodes with kraft pulp or refined fibers showed the lowest electrical resistivity. The specific capacitances of all EDLCs were surprisingly similar, but slightly lower for the EDLC with CNFs. The same electrode sample with CNFs also showed a slightly higher equivalent series resistance (ESR), compared to those of the other EDLCs. Graphite dispersions with MFC showed the best dispersion stability. 

Emneord
Cellulose, Electric double-layer capacitor, Graphite, Nanocellulose, Nanocomposite, Supercapacitor
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-32766 (URN)10.1016/j.matdes.2017.12.041 (DOI)000424945300031 ()2-s2.0-85040002856 (Scopus ID)
Tilgjengelig fra: 2018-01-30 Laget: 2018-01-30 Sist oppdatert: 2018-07-19bibliografisk kontrollert
Blomquist, N., Wells, T., Andres, B., Bäckström, J., Forsberg, S. & Olin, H. (2017). Metal-free supercapacitor with aqueous electrolyte and low-cost carbon materials. Scientific Reports, 7, Article ID 39836.
Åpne denne publikasjonen i ny fane eller vindu >>Metal-free supercapacitor with aqueous electrolyte and low-cost carbon materials
Vise andre…
2017 (engelsk)Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikkel-id 39836Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Electric double-layer capacitors (EDLCs) or supercapacitors (SCs) are fast energy storage devices with high pulse efficiency and superior cyclability, which makes them useful in various applications including electronics, vehicles and grids. Aqueous SCs are considered to be more environmentally friendly than those based on organic electrolytes. Because of the corrosive nature of the aqueous environment, however, expensive electrochemically stable materials are needed for the current collectors and electrodes in aqueous SCs. This results in high costs for a given energy-storage capacity. To address this, we developed a novel low-cost aqueous SC using graphite foil as the current collector and a mix of graphene, nanographite, simple water-purification carbons and nanocellulose as electrodes. The electrodes were coated directly onto the graphite foil by using casting frames and the SCs were assembled in a pouch cell design. With this approach, we achieved a material cost reduction of greater than 90% while maintaining approximately one-half of the specific capacitance of a commercial unit, thus demonstrating that the proposed SC can be an environmentally friendly, low-cost alternative to conventional SCs.

sted, utgiver, år, opplag, sider
Nature Publishing Group, 2017
Emneord
Supercapacitor, EDLC, Graphene, Graphite, Nanoparticles
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-29827 (URN)10.1038/srep39836 (DOI)000391182900001 ()2-s2.0-85008701942 (Scopus ID)
Forskningsfinansiär
Swedish Energy Agency
Merknad

Published online:05 January 2017

Tilgjengelig fra: 2017-01-06 Laget: 2017-01-06 Sist oppdatert: 2019-05-02bibliografisk kontrollert
Andres, B., Engström, A.-C., Blomquist, N., Forsberg, S., Dahlström, C. & Olin, H. (2016). Electrode Mass Balancing as an Inexpensive and Simple Method to Increase the Capacitance of Electric Double-Layer Capacitors. PLoS ONE, 11(9), 1-12, Article ID e0163146.
Åpne denne publikasjonen i ny fane eller vindu >>Electrode Mass Balancing as an Inexpensive and Simple Method to Increase the Capacitance of Electric Double-Layer Capacitors
Vise andre…
2016 (engelsk)Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 9, s. 1-12, artikkel-id e0163146Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Symmetric electric double-layer capacitors (EDLCs) have equal masses of the same active material in both electrodes. However, having equal electrode masses may prevent the EDLC to have the largest possible specific capacitance if the sizes of the hydrated anions and cations in the electrolyte differ because the electrodes and the electrolyte may not be completely utilized. Here we demonstrate how this issue can be resolved by mass balancing. If the electrode masses are adjusted according to the size of the ions, one can easily increase an EDLC's specific capacitance. To that end, we performed galvanostatic cycling to measure the capacitances of symmetric EDLCs with different electrode mass ratios using four aqueous electrolytes-Na2SO4, H2SO4, NaOH, and KOH (all with a concentration of 1 M)-and compared these to the theoretical optimal electrode mass ratio that we calculated using the sizes of the hydrated ions. Both the theoretical and experimental values revealed lower-than-1 optimal electrode ratios for all electrolytes except KOH. The largest increase in capacitance was obtained for EDLCs with NaOH as electrolyte. Specifically, we demonstrate an increase of the specific capacitance by 8.6% by adjusting the electrode mass ratio from 1 to 0.86. Our findings demonstrate that electrode mass balancing is a simple and inexpensive method to increase the capacitance of EDLCs. Furthermore, our results imply that one can reduce the amount of unused material in EDLCs and thus decrease their weight, volume and cost.

Emneord
Mass balancing, capacitance, electric double layer capacitor, EDLC, electrode, electrolyte, electrode mass ratio, ion size ratio
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-29083 (URN)10.1371/journal.pone.0163146 (DOI)000383893200073 ()2-s2.0-84992186879 (Scopus ID)
Tilgjengelig fra: 2016-10-10 Laget: 2016-10-10 Sist oppdatert: 2017-11-30bibliografisk kontrollert
Blomquist, N. (2016). Large-Scale Nanographite Exfoliation for Low-Cost Metal-Free Supercapacitors. (Licentiate dissertation). Sundsvall: Mid Sweden University
Åpne denne publikasjonen i ny fane eller vindu >>Large-Scale Nanographite Exfoliation for Low-Cost Metal-Free Supercapacitors
2016 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
sted, utgiver, år, opplag, sider
Sundsvall: Mid Sweden University, 2016. s. 34
Serie
Mid Sweden University licentiate thesis, ISSN 1652-8948 ; 125
HSV kategori
Identifikatorer
urn:nbn:se:miun:diva-29720 (URN)978-91-88025-74-6 (ISBN)
Presentation
2016-08-31, O102, Sundsvall, 10:30 (engelsk)
Veileder
Merknad

Vid tidpunkten för framläggningen av avhandlingen var följande delarbeten opublicerade: delarbete 2 inskickat.

At the time of the defence the following papers were unpublished: paper 2 submitted.

Tilgjengelig fra: 2016-12-21 Laget: 2016-12-21 Sist oppdatert: 2016-12-21bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-4303-2585