Johnson Controls’ Lithium-ion batteries power Hybrid Range Rover

18 December 2014

Johnson Controls is supplying the Lithium-ion battery pack for the Hybrid Range Rover (earlier post), announced in 2013. Production of the cells and complete battery systems is underway at Johnson Controls’ manufacturing facility in Holland, Michigan.

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Cutaway of the Li-ion battery pack for the Range Rover. Click to enlarge.

The Range Rover Hybrid powertrain features three driver-selectable modes and combines Land Rover’s popular 3.0-liter SDV6 diesel engine with a 35kW electric motor integrated with the 8-speed ZF automatic transmission. The hybrid system, including lithium-ion battery pack, inverter and electric motor weighs less than 120 kg (282 lbs). Fuel consumption is 6.4 l/100 km (36.7 mpg US) on the combined cycle, with CO₂ emissions of 169 g/km.

The Hybrid Range Rover vehicles are being made at Land Rover’s advanced manufacturing center in Solihull, England.

Iogen and Raízen begin production of cellulosic ethanol in Brazil

18 December 2014

Cellulosic biofuel technology developer Iogen Corporation and Raízen, one of the world’s largest producers of sugarcane ethanol, have begun production of cellulosic ethanol on schedule at Raízen’s newly expanded Costa Pinto sugar cane mill in Piracicaba, São Paulo, Brazil.

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Raízen broke ground on the $US100 million “biomass-to-ethanol” expansion just over one year ago. The new facility will convert biomass such as sugar cane bagasse and straw into 40 million liters (10.6 million gallons US) per year of cellulosic biofuel. It will also be the first large-scale commercial implementation of Iogen Energy’s cellulosic ethanol technology, which the company developed and has extensively proven in its Ottawa demonstration facility.

Pedro Mizutani, Raízen’s Executive Vice President, said that continuous commercial production will commence with the upcoming 2015 harvest season. Raízen has already announced that, given a success at Costa Pinto, it intends to deploy Iogen Energy’s technology in seven more Raízen sugar cane mills.

We plan to be producing up to 1 billion liters [264 million gallons US] of cellulosic biofuel from bagasse and cane straw by 2024.

Raízen is a joint venture between Royal Dutch Shell and Brazilian ethanol company Cosan SA. Raízen produces more than 2.2 billion liters [581 million gallons US] of ethanol annually, 4.5 million tons of sugar, and has installed capacity of 934 MW of electric energy derived from sugar cane bagasse. The company has more than 5,200 service stations for retail fuel distribution in Brazil, more than 900 convenience stores, 60 fuel distribution depots, and aviation fuel businesses in 58 airports in Brazil.

Rice U team uses new computational methodology to identify high capacity MOFs for on-board natural gas storage

18 December 2014

Researchers from Rice University, Lawrence Berkeley National Laboratory and UC Berkeley have developed a computational methodology to support the experimental exploration of potential high-capacity metal organic frameworks (MOFs) for use in on-board storage of natural gas. The advantages to using MOFs as a storage medium are many and start with increased capacity over the heavy, high-pressure cylinders in current use.

In a paper in the ACS Journal of Physical Chemistry C, they report identifying 48 materials with higher predicted deliverable capacity (at 65 bar storage, 5.8 bar depletion, and 298 K) than MOF-5—the currently best available for the natural gas storage application. The best material identified by the researchers has a predicted deliverable capacity 8% higher than that of MOF-5.

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MOFs are nanoscale compounds of metal ions or clusters known as secondary building units (SBUs) and organic binding ligands, or linkers. These linkers hold the SBUs together in a spongy network that can capture and store methane molecules in a tank under pressure. As the pressure is relieved, the network releases the methane for use.

Due to their high porosities, high surface area, and tunable chemistry, MOFs are regarded as a promising class of nano-porous materials. Potential applications of MOFs include drug delivery, sensing, purification, catalysis, and gas storage. In the gas storage application, in particular, MOFs appeal as a competitive alternative to other materials, such as zeolites, because of their potentially higher performance and adjustability. Computation predictions have extended the number of potential MOFs to 100, 000.

From a practical point of view, one can only synthesize and test a small fraction of all possible MOF materials, and computation predictions are useful for suggesting promising sets of MOFs to synthesize. Existing prediction methods focus on simulation of the self-assembly process, placing known SBUs into candidate periodic networks. A limitation of these methods is that only pre-existing linkers are considered, with little or no exploration of the space of possible organic linkers.
We here develop a de novo evolutionary algorithm to explore the composition and configuration space of linker molecules to optimize methane deliverable capacity in predicted MOFs.

Since the linker, SBU, and topology can all vary, the chemical search space is nearly infinite. This poses a fundamental problem for the current methods of library generation, which are all based on brute force enumeration, as the number of compounds grows exponentially with length and branching structure of the linkers. The vast majority of these potential have poor methane delivery performance. Thus, it is desirable to efficiently sample the part of the MOF composition space with favorable materials properties. We tackle this issue by using an evolutionary algorithm to rapidly explore MOF linker composition space, among MOFs with high predicted methane deliverable capacity.

One of 48 metal organic frameworks discovered through an algorithm developed at Rice to explore compounds that excel at storing methane. Here, molecules known as secondary building units (top left) and organic binding ligands, or linkers (top right) can be used in a chemical process to produce the metal organic framework seen at bottom. Courtesy of the Deem Research Group. Click to enlarge.

The team led by Rice bioengineer Michael Deem used a custom algorithm not only quickly to design new MOF configurations able to store compressed natural gas with a high “deliverable capacity,” but also to design ones that can be reliably synthesized from commercial precursor molecules. The algorithm also keeps track of the routes to synthesis.

The program adhered to standard DOE conditions that an ideal MOF would store methane at 65 bar (atmospheric pressure at sea level is one bar) and release it at 5.8 bar, all at 298 kelvins (about 77 degrees Fahrenheit). That pressure is significantly less than standard CNG tanks, and the temperature is far higher than liquid natural gas tanks that must be cooled to minus 260 degrees F.

Lower pressures mean tanks can be lighter and made to fit cars better, Deem said. They may also offer the possibility that customers can tank up from household gas supply lines.

The Deem group’s algorithm was adapted from an earlier project to identify zeolites. The researchers ran Monte Carlo calculations on nearly 57,000 precursor molecules, modifying them with synthetic chemistry reactions via the computer to find which would make MOFs with the best deliverable capacity.

Our work differs from previous efforts because we’re searching the space of possible MOF linkers specifically for this deliverable capacity. We’re very keen to work with experimental groups, and happy to collaborate. We have joint projects underway, so we hope some of these predicted materials will be synthesized very soon.

The researchers hope to begin real-world testing of their best MOF models.

Yi Bao, a graduate student in Deem’s lab at Rice’s BioScience Research Collaborative, is lead author of the paper. Co-authors are Richard Martin and Maciej Haranczyk of the Lawrence Berkeley National Laboratory and Cory Simon and Berend Smit of the University of California-Berkeley. Deem is chair of Rice’s Department of Bioengineering and the John W. Cox Professor of Biochemical and Genetic Engineering.

The DOE Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, supported the research. The researchers utilized the National Science Foundation-funded DAVinCi supercomputer administered by Rice’s Ken Kennedy Institute for Information Technology.

Resources

• Yi Bao, Richard Luis Martin, Cory M Simon, Maciej Haranczyk, Berend Smit, and Michael W Deem, “In Silico Discovery of High Deliverable Capacity Metal-Organic Frameworks,” J. Phys. Chem. C, Just Accepted Manuscript
  doi: 10.1021/jp5123486

New high-voltage electrolyte additive supports high energy density and stability in LMNC Li-ion battery; 2x energy density over LiCoO2

18 December 2014

Discharge capacity and cycle numbers for LMNC cathode with and without DFDEC in the electrolyte. Pham et al. Click to enlarge.

A team led by researchers at Chungnam National University (S. Korea) has developed a novel high-voltage electrolyte additive, di-(2,2,2 trifluoroethyl)carbonate (DFDEC), for use with the promising lithium-rich layered composite oxide high-energy cathode material xLi₂MnO₃·(1-x)LiMO₂ (M = Mn, Ni, Co).

In a study reported in the Journal of the Electrochemical Society, the team, led by Professor Seung-Wan Song, operated a 0.6Li₂MnO₃·0.4LiNi_0.45Co_0.25Mn_0.3O₂ (Li_1.2Mn_0.525Ni_0.175Co_0.1O₂, LMNC) cathode at 2.5–4.8 V with 5 wt% of the fluorinated linear carbonate DFDEC as an additive. The cathode with DFDEC-enhanced electrolyte outperformed that in electrolyte only, delivering a high capacity of 250 mAhg⁻¹ with an excellent charge-discharge cycling stability at the rate of 0.2C. A full cell based on the LMNC cathode and graphite anode successfully demonstrated doubled energy density (∼278 Wh kg⁻¹) compared to ∼136 Wh kg⁻¹ of a commercialized cell of graphite/LiCoO₂ as well as an excellent cycling stability.

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Proposed interfacial reaction and SEI formation mechanisms of the Li_1.2Mn_0.525Ni_0.175Co_0.1O₂ cathode during high-voltage (4.8 V) cycling in (top right) electrolyte only and (bottom right) with DFDEC additive.

The researchers determined that with the use of DFDEC, the cathode surface is effectively passivated by a stable SEI composed of DFDEC decomposition products, which inhibit a detrimental metal dissolution and structural cathode degradation. Pham et al. Click to enlarge.

Enabling the high-energy and safety lithium-ion battery requires the development of high-capacity and high-voltage cathode, high-capacity anode and accordingly functional electrolyte with high voltage stability, interfacial compatibility with electrodes and safety. Li-rich layered composite oxides, represented xLi₂MnO₃·(1-x)LiMO₂ (M = Mn, Ni, Co), has been appealing as high-energy cathode materials because of a possible high specific capacity as much as or higher than 250 mAhg⁻¹ on the high-voltage operation above 4.6 V vs. Li/Li⁺, which can provide enhanced energy density compared to ∼136 Wh kg⁻¹ by LiCoO₂ in a commercial battery. Cycling stability, rate capability and safety are however often arduous to achieve at high-voltage operation (4.3 V vs. Li/Li⁺), due to structural instability at a highly charged (Li+- deintercalated) state and voltage fade with cycling, and in particular, serious oxidative decomposition of conventional electrolyte.

Enabling the high-energy lithium-ion battery with high-voltage cathode relies on an electrolyte breakthrough and the SEI stabilization. We have been searching for and screening a number of fluorinated linear carbonates as high-voltage electrolyte additives … The use of an additive rather than solvent comprises a low cost. … In this work, we report high-performance of the half-cell and full-cell with 4.8 V LMNC cathode and a novel electrolyte additive of di-(2,2,2 trifluoroethyl)carbonate (DFDEC) for the first time for a high-energy lithium-ion battery.

Cycling in electrolyte without the additive resulted in a structural degradation from surface to bulk, particle cracking, metal dissolution and oxygen loss, all of which degrades performance.

The team’s surface chemistry studies indicated that DFDEC leads to the formation of a stable SEI consisting of its decomposition, together with electrolyte decomposition products, which let the cathode withstand high-voltage operation to 4.8 V.

Resources

• Hieu Quang Pham, Kyoung-Mo Nam, Eui-Hyung Hwang, Young-Gil Kwon, Hyun Min Jung, and Seung-Wan Song (2014) “Performance Enhancement of 4.8 V Li_1.2Mn_0.525Ni_0.175Co_0.1O₂ Battery Cathode Using Fluorinated Linear Carbonate
  as a High-Voltage Additive,” Journal of The Electrochemical Society, 161 (14) A2002-A2011 doi: 10.1149/2.1141412jes]