Patent analysis and product survey on use of nanomaterials in lithium-ion batteries

(Nanowerk Spotlight) The efforts undertaken in developing renewable energy sources to reduce our dependence on fossil fuels include major research and investment in advanced electricity storage technologies. Among the various existing technologies, lithium (Li) batteries are considered as the most competitive power source because of their high energy density, superior power capability, design flexibility and longer lifespan.
Use of lithium in batteries was first reported by A. V. Fraioly et al.1) in 1968, and the first rechargeable Li battery was proposed by M.S Whittingham2-3). Further, the concept of secondary Li battery was first demonstrated by D.W Murphy et al. 4) in 1978. Ground-breaking cathode materials (lithium cobalt oxide) research was carried out by a team led by John B. Goodenough5-6) following which Sony brought out the first commercial lithium ion battery in 1991. The first use of any nanomaterial was reported by Hyperion Catalysis International Inc. wherein they have used carbon fibril as anode material of lithium battery7.
Li-ion batteries have become the dominant power source for portable electronic devices – like cell phones, laptops, digital cameras etc. – due to their superior energy density and high cell voltage. They are also the technology of choice for the large emerging markets of hybrid, plug- in hybrid and electric vehicles and aerospace applications.
To meet the future challenges of energy storage, a new generation of Li-ion batteries with excellent performance, long cycle life, safety and reliability are needed not only for applications in consumer electronics, but especially for clean energy storage and use in all electric vehicles and for aerospace applications.
An emerging understanding of nanoscience and the developments in the field of nanotechnology have offered solutions to energy storage applications. Advances in electrochemistry, surface science, and materials science have stimulated the use of nanomaterials in more efficient energy storage and battery systems. Nanomaterials have the potential to significantly enhance the performance of lithium-ion batteries. The prominent impact in terms of high power is envisaged due to their reduced dimensions that enable to achieve far higher surface/interface Li storage and intercalation/deintercalation rates.
The present study has been conducted to get an overview of the current patent landscape of rechargeable Li-ion battery, with a focus on the recent developments on nanomaterials and nanotechnologies used for anode, cathode, and electrolyte materials, and the impact of nanomaterials on the performance of rechargeable lithium batteries. Effort has also been taken to identify key players, emerging trends and applications in this area.
Figure 1 depicts the patenting trend in the field of nanomaterials-based Li-rechargeable batteries, as obtained from the analysis of relevant patents. The research activity in this area was initiated in 2000, and since then, there has been a continuous growth in the patenting trend. However, an exponential rise in the R&D efforts can be seen from 2009 onwards due to the commercial success in using nanomaterials for Li-ion batteries.
Annual growth of patents related to nanomaterial-based Li-ion rechargeable batteries
Fig. 1: Annual growth of patents related to nanomaterial-based Li-ion rechargeable batteries (Source: www.thomsoninnovation.com)
The patent applications have been classified based on the focus of inventions as presented in Fig. 2 below. It is apparent from the figure that 60% of the patent applications have been filed exclusively for nanomaterials used in Li-ion batteries. Further, 26% of the patents, in their claims, have included research on materials as well as fabrication of Li-ion batteries.
Even though the first direct use of nanomaterials in the fabrication of Li-ion battery has been reported in 19937, analysis shows, this trend has been increased significantly in the last few years due to a significant amount of research that is being carried out in the area of nanomaterials as well as due to the increase in the demand for high performance Li-ion batteries. Matsushita Electric Ind. Co., Ltd. has been focusing their research activity, mainly in the fabrication of Li-ion batteries that incorporate nanomaterials whereas BASF, BYD Co., Ltd. and Hon Hai Precision Ind. Co, Ltd have focused their R&D activity in developing nanomaterials.
Segmentation of patents based on focus of the claimed invention
Fig. 2: Segmentation of patents based on focus of the claimed invention.
An analysis of patents reveals that the majority of developments in advanced rechargeable batteries are directed towards wider applications in three distinctive categories:
  • the ever-expanding 3C (computer, communication, and consumer electronics) devices
  • grid energy storage devices for wind and solar power
  • emerging electric vehicles.
  • Further analysis shows that patents have also been claimed for the use of Li-ion batteries in various biomedical applications such as neurological stimulation device, cardiac defibrillator, cardiac pacemaker, cardiac contractility module, cardiac contractility modulator, cardioverter, drug administration device, cochlear implant, hearing aid, diagnostic recorder, sensors and in telemetry device as well as spacecraft applications.
    Various nanomaterials are being used in different components of Li-ion battery such as anode, cathode, electrolyte, and separator. Nanomaterials, providing higher reactivity and short diffusion length for Li ions, enable researchers to modify existing electrodes.
    Figure 3 gives the categorization of patents focused on various components of Li-ion battery for which nanomaterials are being developed. It becomes very clear from the figure that research activity on nanomaterials is concentrated for anode development followed by cathode. Nanotechnology has been implemented in electrolyte and separator components as well. Even though the research activity has been intense in the field of anode materials which is centered on various carbon-based materials and lithium alloys, diverse nanomaterials are being explored for cathode applications.
    Catergorization of patents based on different components of Li-ion battery for which nanometrials are being developed
    Fig. 3: Categorization of patents based on different components of Li-ion battery for which nanomaterials are being developed.
    Analysis reveals that nanocrystalline intermetallic alloys, nanosized composite materials (e.g. Polymer composites), carbon nanotubes/nanofibers and nanosized transition-metal oxides are all promising new anode materials, whereas nanosized LiCoO2, LiFePO4, LiMn2O4, carbon nanotubes and nanofibers show higher capacity and better cycle life as cathode materials for Li-ion batteries.
    Nanosized metal-oxide powders, metal nanoparticles and CNTs were also added to polymer electrolytes to improve the performance of the electrolyte for all solid-state lithium rechargeable batteries. Similarly, nanotechnologies have been used for separators (e.g. nanostructured polyamide). Different synthetic routes have been discussed in the patents for the fabrication of nanostructured materials that can alloy with Li, which includes ball milling, sol-gel, electrospinning and electrodeposition. Chemical vapor deposition, electrostatic spray deposition, ultrasonication, polyol method, functional coatings, heat treatment, plasma processing and gamma-ray irradiation etc. are also being used for the synthesis or processing of nanomaterials for their use in different components of Li-ion battery.
    Figure 4 highlights the top 10 assignees of patents published/granted in the area of nanomaterials-based Li-ion battery. The analysis reveals that South Korea-based Samsung SDI Co, Ltd is the leader with 24 patent applications to their credit followed by BASF, Germany and Hon Hai Precision Industry Co, Ltd., Taiwan, with 14 patent applications each during the analysis period. Samsung SDI Co, Ltd. has been involved in the development of carbon nanotube/nanofibers and silicon nanoparticle based anode materials for Li-ion battery which will be used in consumer electronics applications. Similarly, BASF has involved in material based research where the lithium iron phosphate and CNT/carbon nanofibers are being developed as cathode materials for batteries. Analysis reveals that Mitsubishi Materials Corp, LG Chem, Ltd. and Dr. Jang (CEO of Nanotek Instruments, Inc.), have also done significant amount of research in the area of electrodes.
    Top 10 assignees for nanomaterials based Li-ion battery
    Fig. 4: Top 10 assignees for nanomaterials based Li-ion battery.
    Figure 5 (a) and (b) indicate the country-wise and region-wise distribution of patents in the area of nanomaterials-based Li-ion batteries. The maximum number of patent applications (149) related to the subject were filed by assignees from Japan followed by United States (133), China (132), and South Korea (120). Further analysis shows that Taiwan has also done remarkable amount of research with 27 patents to their credit. In terms of regions, Asia-Pacific (72%) is the front-runner in the nanotechnology-based Li-ion battery patent filing followed by North America (23%) and Europe (4%).
    patenting activity on nanomaterial-based Li-ion battery based on countries
    patenting activity on nanomaterial-based Li-ion battery based on regions
    Fig. 5: Segmentation of patenting activity on nanomaterial-based Li-ion battery based on (a) countries and (b) geographic region.
    Global Market Scenario
    The global market for secondary lithium-ion batteries was $8.4 billion in 20108). Asia accounts for approximately 48% of global market share followed by North America (26.3%) and Europe (22.9%). Further, consumer applications account for about 71.4% ($6.0 billion), while industrial applications account for about 28.6% ($2.4 billion) of total revenues.
    The global market for nano-enabled batteries is expected to reach $1.13 billion by 2013 from $169 million in 2008 with an average annual growth rate (AAGR) of 46.3%9). By 2013, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) and specialty electric vehicles will have 84.7% share of the global market, which shows AAGR of 71.8% from 20089. According to the Electronics.ca report, the global market for nanomaterial-enabled lithium ion battery systems was $63 million in 2010, and expected to grow at a compound annual growth rate (CAGR) of 37 %, rising to $575million by 201710). The major driver for the market growth is the increasing acceptance of nano-enabled Li-ion battery. However, Li-ion battery industry is also facing various challenges regarding cost and safety.
    Some of the key drivers include the following:
    Key Drivers
  • Higher power and higher energy
  • Increased energy density
  • Improved charge/discharge capability
  • Enhanced shelf life
  • Lighter weight
  • Enhanced safety measures with respect to the possibility of catching fire
  • Market Drivers
  • Demand for eco-friendly and non-petroleum vehicles especially in the developed countries
  • Higher demand for electric, hybrids, and plug in hybrids vehicles
  • Reduced environmental footprint
  • Some of the key challenges to develop high performance Li-ion batteries include the following:
    Challenges
  • Higher cost
  • Performance (power and energy) over a wide temperature range (-30 to 52?C)
  • Calendar life, as 15-year calendar life is yet to be achieved
  • Compatibility issues, for eg. problem of agglomeration and processing difficulties
  • Safety issues related to nano powders as in the case of Li4Ti5O12 nano-powder, commercialization of which was regulated due to the fire hazards associated with this material
  • Environmental effects and health risks posed by constituent materials
  • Nanotechnology-enabled Li-ion battery Products available in the Market
    To get a clearer picture of commercialization of nanotechnology-enabled Li-ion batteries, a survey has been done for various players present in the market.
  • In 2005, Japanese electronics giant Sony Corporation had launched industry's first nanotechnology-based "Nexelion" Li-ion battery with a nanostructured anode made from a tin-cobalt-carbon (Sn-Co-C) composite. In addition to this, in 2009 Sony Corporation has launched high-power, long-life Li-ion battery using olivine (magnesium iron silicate (Mg,Fe)2SiO4)-type lithium iron phosphate as the cathode material.
  • A123 Systems, Inc. a ten-year old listed company manufactures nanophosphate™-based lithium-ion batteries that has high energy density and power, lighter weight, longer cycle life, and excellent safety performance. These batteries will be used in a variety of applications, including hybrid electric vehicles, electronic devices, and power tools. The nanophosphate lithium-ion technology is based on patented technology (US granted patent No. 7842420) developed at the Massachusetts Institute of Technology (MIT). A123 Systems, Inc. has earmarked more than $1 billion investment to capacity expansion for mass production of the advanced battery cells and systems to meet increasing global demand.
  • Altair Nanotechnologies, Inc. a publicly-traded corporation designs, manufactures, and delivers lithium titanate electrode materials and energy storage systems such as lithium-ion batteries for military and mass transportation applications. Altair Nanotechnologies Inc., has developed NanoSafe™ lithium-ion batteries, which takes only a 10-minute charge time, is being supplied to Phoenix Motor Cars (U.S.) and The Lightning Car Company (U.K.). An US patent (No.6890510) and a European Patent (EPO, patent No.1409409) were granted for this technology, which cover nano-lithium titanate technology including a process for making lithium titanate.
  • EcoloCap Solutions, Inc. a publicly-traded corporation and its subsidiaries Micro Bubble Technologies, Inc., K-MBT Inc. (Korea), and EcoloCap Solutions Canada, Inc. design, develop, and manufacture carbon nanotubes (CNTs)-based lithium-ion batteries to provide efficient alternative energy solutions as well as supply CNTs-based electrodes to the Li-Ion battery manufacturers. In India, EcoloCap Solutions, Inc is going to start a lithium-ion battery manufacturing unit as the government of India has permitted for an initial production of 10,000 units. EcoloCap Solutions, Inc. has also signed a memorandum of understanding (MOU) between Spice Jet, Star Bus, and Argentum Engines Pvt. Ltd to supply Li-ion battery systems.
  • Zhong Qiang Power-Tech Co, Ltd, a wholly-owned subsidiary of Advanced Battery Technologies, Inc. (ABAT), a Chinese company has been manufacturing Polymer-Lithium-Ion (PLI) battery by using lithium titanate spinel nanomaterials provided by Altair Nanotechnologies, Inc. The PLI batteries are being used in cell phones, notebook computers, electric vehicles, mine-use lamps, and other personal electronic devices. The Company's proprietary technology has been developed at the Harbin Institute of Technology (HIT) and has received a Chinese patent (CN patent no.10087299) as well as US patent (no. 6994737).
  • Ener1, Inc. a publicly-traded company has developed nanotechnology based lithium-ion batteries for the automobile (electric, hybrid, and plug-in hybrid), military, and grid storage applications. In 2010, Ener1, Inc. has signed a memorandum of understanding (MOU) with Russia's Federal Grid Company to develop and supply high-performance lithium-ion battery systems.
  • mPhase Technologies, Inc. a wholly-owned subsidiary of AlwaysReady, Inc. and a publicly-traded corporation is engaged in the development of nanotechnology-based advanced energy storage devices and ultra sensitive magnetometers. Recently, mPhase Technologies, Inc. has launched mPower Emergency Illuminator™, an innovative nanotechnology-based active reserve lithium-ion battery for consumer electronics, defense, and industrial applications. For this technology mPhase Technologies, Inc has granted US patent (No.7618746). The mPower Emergency Illuminator™ is based on ZnMnO2 and LiMnO2 chemistries and consists of a three-cell array. Power is produced when the first cell in the battery is activated and when first cell dies, the second cell is triggered and followed by the third cell.
  • Japanese electronics manufacturer Hitachi, Ltd. and Hitachi Vehicle Energy, Ltd. develops and manufactures nanotechnology-based lithium-ion batteries by using lithium manganese oxide spinel (LIMn2O4), as cathode material. Hitachi claims that Li-Ion battery produced using this technology are having the world's highest power density of 4,500W/kg.
  • Japanese electronics giant Toshiba Corp. has launched Li-ion battery (Super Charge Ion Battery (SCiB)™) with a lithium titanate nanocrystal-based anode material. SCiB™ battery is designed to offer 90% charge capacity in as fast as 10 minutes and offers excellent characteristics such as rapid charging capability, long life cycle with minimal capacity loss even after 6,000 charge-discharge cycles.
  • Contour Energy Systems, a spin-off of the collaboration between California Institute of Technology (Caltech) and Centre National de la Recherche Scientifique (CNRS, the French National Center of Scientific Research), founded in 2007, is a next-generation battery company that manufactures Li-ion batteries as well as primary lithium carbon fluoride batteries. Contour Energy Systems has an exclusive technology licensing agreement with Caltech as well as strategic partnerships with Jet Propulsion Laboratory, NASA, Schlumberger. Recently, it has acquired a carbon nanotube technology to develop electrodes through an exclusive technology licensing agreement with Massachusetts Institute of Technology (MIT) to improve the power capability of lithium-ion batteries.
  • Valence Technology, Inc. a publicly-traded corporation designs, develops, and manufactures lithium iron magnesium phosphate (LiFeMgPO4) advanced energy systems by using a nanophosphate technology. The products include U-Charge® RT, and U-Charge® XP Li-Ion battery.
  • Pihsiang Energy Technology Co., Ltd (PHET) a Taiwanese energy technology company has an exclusive patent license agreement with Phostech Lithium, Inc. (materials technologies) to make, use, and sell C-LiFePO4 batteries in all applications such as electric bikes, electric scooters, power wheelchairs, and others. PHET is the first mass manufacturer of C-LiFePO4 battery cells and packs throughout the world.
  • Angstron Materials Inc., the world's largest producer of nano graphene platelets (NGPs) has signed a memorandum of understanding (MOU) with K2 Energy Solutions, a manufacturer of rechargeable battery systems to carry out a Department of Energy (DOE) research project to develop hybrid nanomaterials-based (graphene platelet) high-capacity anodes for Li-Ion batteries.
  • US Photonics, Inc. is developing cutting edge Li-Ion batteries by utilizing conductive polymers, carbon nanotubes (CNTs), Nitinol, sol gels and aerogels in their research for new anode and cathode materials, separator technology, and emerging electrolyte impregnated polymers.
  • Japan's Nissan Motor Co., Ltd is going to launch advanced Li-ion battery in 2012, to support the rollout of electric vehicles from the Renault-Nissan Alliance in Europe with a total production capacity of 50,000 units per year. Nissan has spent nearly two decades of R&D to bring out nanotechnology-based Li-ion battery (manganese electrode with laminated structure) on electric vehicles. NEC Corporation will be supplying nanomaterials for mass production.
  • LG Chem Michigan, Inc. (LGCMI), a wholly-owned North American subsidiary of LG Chem,Ltd (Korea's largest chemical and rechargeable battery maker), was established in 2010 to manufacture Li-ion battery cells. The U.S. Department of Energy's (DOE) Argonne National Laboratory and LG Chem, Ltd. have signed a licensing agreement in 2011 to make and use Argonne's patented cathode material technology in lithium-ion battery cells.
  • Electrovaya, Inc., headquartered in Ontario, Canada, designs, develops and manufactures Lithium Ion SuperPolymer® battery which is based on nanostructured lithiated manganese oxide material. Electrovaya, Inc. battery products find applications in utility scale energy storage, electric transportation, smart grid power, and consumer and healthcare markets. Electrovaya has more than 150 global patents on its Lithium Ion SuperPolymer® battery technology and associated system technologies which include a US granted patent (6815121), EPO patent (1377477) and Australian patent (757759). In April 2011, Electrovaya, Inc. has tied up with Hero Electric, a subsidiary of the Hero Group, India to supply its Lithium Ion SuperPolymer® batteries for Hero Electric's two-wheeled electric vehicles that is likely to be launched in the Canadian market in the third quarter of 2011. Earlier, Electrovaya, Inc has signed a contract with Chrysler Group LLC, a multinational auto maker headquartered in the Detroit, to provide lithium-ion batteries for a plug-in hybrid version of the auto maker's Dodge Ram pickup truck as well as partnered with India's Tata Motors to produce the electric version of Tata's Indica hatchback.
  • SAFT America, Inc. a world specialist in the design and manufacture of advanced Li-ion batteries for high performance applications such as transportation, industrial infrastructure, space and defense. The group is the world leader in Li-ion satellite batteries. Saft has delivered its Super-Phosphate™ nanostructured Li-ion phosphate (LiFePO4) battery technology for applications in military hybrid electric vehicles, airborne power, pulse power for unmanned applications, and naval power for torpedoes, actuators and launchers.
  • Seeo, Inc., a University of California, Berkeley spin-off founded in 2007 with an exclusive license from Lawrence Berkeley National Laboratory, has developed nanostructured solid-state Li-ion batteries. Seeo uses thin films of nano-structured polymer platform as the solid electrolyte that provides safety and long-term stability.
  • Raw materials suppliers for nanotechnology-based lithium-ion batteries
  • In 2010, the world's largest chemical conglomerate, BASF has started production unit for Nickel-Cobalt-Manganese (NCM) cathode materials for use in lithium-ion batteries. The technology has been borrowed via licensing agreement from the U.S. Department of Energy's (DOE) Argonne National Laboratory for mass production and market Argonne's patented (US patent no. 7314684) cathode materials. The products include HED™ NCM-111, HED™ NCM-424, and HED™ NCM-523.
  • NanoEner, Inc. a wholly-owned subsidiary of Ener1, Inc., produces nanostructured electrodes based on LiMn2O4, LiCoO2, MnO2, C, and Si for energy storage devices such as lithium-ion batteries for hybrid electric vehicles, handheld power tools, and other applications.
  • NanoeXa Corporation, USA manufactures Layer-to-Layer Nickel-Cobalt-Manganese (NCM) cathode materials for lithium-ion batteries. The technology has been licensed from the US Argonne National Laboratory.
  • Nexeon® Ltd, a UK-based battery materials and licensing company produces silicon anode materials for lithium-ion batteries. Nexeon's patented (US patent no. 7402829, 7683359, and 7842535) silicon anode technology overcome the previous problems of poor charging, cycle life, etc as well as provide lighter batteries with more power and charging capacities.
  • Nanostructured & Amorphous Materials, Inc. (NanoAmor), an American nanomaterials company, is involved in the manufacturing of nanostructured materials and their dispersions. It supplies CNT-based electrode additives of highly conductive multi-walled carbon nanotubes for Li-Ion batteries.
  • NEI Corporation, USA a leading manufacturer of nanomaterials, supplies cathode materials for Li-Ion batteries that include Lithium Titanate (Li4Ti5O12) Nanomyte™ BE-10, Lithium manganese oxide (LiMn2O4) Nanomyte™ BE-30, Lithium Nickel Cobalt Aluminum Oxide (LiNixCoyAlzO2) Nanomyte™ BE-40, and Lithium Manganese Nickel Oxide Nanomyte™ SP-10. These materials are widely used in Li-ion batteries due to their high energy density, high power, and good cycle life.
  • Phostech Lithium, Inc. a wholly-owned subsidiary of S?d-Chemie AG, is the leading manufacturer and supplier of carbon coated Lithium Iron Phosphate (C-LiFePO4) cathode materials as well as lithium titanate spinel oxide (Li4Ti5O12) anode materials for Li-Ion batteries. Phostech Lithium, Inc. has a granted US patent (no.7534408) on C-LiFePO4 technology.
  • Conclusions
    The present analysis on nanotechnology-enabled Li-ion batteries demonstrates that nanomaterials and nanotechnologies are promising for the new generation of Li-ion secondary batteries. Several nanomaterials have been identified, which have great potential to enhance the performance of Li-ion battery. Innovative approaches to materials science and battery engineering are available from a large number of very significant companies like GE, Panasonic Corp, SANYO Electric Co., Ltd., Matsushita Industrial Co., Ltd., NEC Corp, SAFT America, Inc, Toshiba Corp, BYD/Berkshire Hathaway, LG Chem, Ltd., Altair Nanotechnologies, Samsung SDI Co, Ltd, Sony Corp, A123 Systems, Inc. and Altair Nanotechnologies. Diverse applications of Li-ion batteries for clean energy storage applications assure that all major stakeholders such as consumer electronics manufactures, electric and hybrid vehicle manufactures and other high end users are keenly interested in developing new manufacturing techniques, which will bring down the cost of production for widespread deployment.
    References
    1. A.V Fraioly, W.A Barber, A.M Feldman, "Composite Paper Electrode for a Voltaic Cell", US Patent No. 3,551,205, Dec 29, 1970 (Filed on December 5, 1968), Assignee: American Cyanamid Corp
    2. M.S. Whittingham, "Electrical Energy Storage and Intercalation Chemistry", Science (1976) 1126-1127
    3. M. S. Whittingham, "Chalcogenide battery" US Patent No. 4,009,052, February 22, 1977 (Filed on April 5, 1976), Assignee: Exxon Research and Engineering Company
    4. D.W. Murphy, F.J. Di Salvoa, J.N. Caridesa, J.V. Waszczak "Topochemical reactions of rutile related structures with lithium", Materials Research Bulletin, 13 (1978)1395?1402
    5. K. Mizushimaa, P.C. Jonesb, P.J. Wisemanb, J.B. Goodenough, "LixCoO2 (0<x 1): a new cathode material for batteries of high energy density", Materials Research Bulletin, 15 (1980) 783?789
    6. M. M. Thackeray, W. I. F. David, P. G. Bruce, J. B. Goodenough "Lithium insertion into manganese spinels", Materials Research Bulletin, 18 (1983) 461?472
    7. I.Hiroharu, H.Robert, R. Hausslein, "Lithium battery with electrodes containing carbon fibrils", US Patent No. 5,879,836, March 9, 1999 (Filed on September 10, 1993)
    8. "World Lithium-ion Battery Market", June 2010, published by Frost & Sullivan http://www.frost.com/prod/servlet/report-toc.pag?repid=N76F-27-00-00-00
    9. "Nano-enabled Batteries for Portable and Rechargeable Applications: Types, Applications, New Developments, Industry Structure and Global Markets", Feb 2009, published by iRAP, http://www.innoresearch.net/Press_Release.aspx?id=15
    10. "Nanomaterials and the World Lithium Ion Battery Market", February 2011, published by Electronics.ca http://www.electronics.ca/publications/products/Nanomaterials-and-the-World-Lithium-Ion-Battery-Market.html
    By Prajakta S. Kuyate and Vivek Patel, Centre for Knowledge Management of Nanoscience and Technology (CKMNT).

    Become a Spotlight guest author! Join our large and growing group of guest contributors. Have you just published a scientific paper or have other exciting developments to share with the nanotechnology community? Here is how to publish on nanowerk.com.