The integration of electronic systems into flexible, wearable devices has potential applications in medical care and consumer electronics. One bottleneck of such technologies is to develop flexible power sources. Current consumer electronics usually use rechargeable lithium ion batteries as the power source. The batteries are rigid, bulky, heavy and not compatible with all-flexible electronics. The batteries also have safety issues such as being flammable and explosive. Electrochemical supercapacitors are energy storage devices that store energy by electrochemical double layer effect and/or redox reaction based pseudo capacitance effect. They store about one order less energy per weight compared to lithium ion batteries, but they can be rapidly recharged in seconds/minutes, survive more than 100,000 charge-discharge cycles, and operate safely. Researchers at UC Berkeley have developed an approach to make supercapacitors in the form of flexible fabrics to power flexible, wearable electronics. The supercapacitors may be woven into flexible fabrics, which can function as portable or wearable energy sources. Alternatively, they may be made strong and stiff, which can then be used as structural components in electrical vehicle, drones, satellites, and so on, to provide mechanical support and energy at the same time.

There are an estimated 130 million wooden poles that support overhead power lines in the US.  Extreme weather, aging, storms or sabotage can all lead to potential damage of these poles and power lines, which can leave large areas without basic necessities.  Due to this risk, it’s anticipated that power utility companies will deploy sensors and corresponding energy harvesters to better respond to potential damage of this critical electricity grid infrastructure. To address this anticipated mass deployment of sensors and harvesters, researchers at UC Berkeley have developed technology improvements to harvesting of electrical energy from energized conductors carrying alternating currents, such as those on overhead and underground power lines (as well as power-supplying conductors in offices and dwellings).  These enhanced harvesters would improve the economics of deploying sensors across a national power grid.  The Berkeley harvesters can readily provide enough power to supply wireless communication devices, energy storage batteries and capacitors, as well as sensors such as accelerometers, particulate matter measuring devices, and atmospheric sensors.

Surface defects dominate the behavior of minority carriers in semiconductors and optoelectronic devices. Photoluminescence quantum yield (QY), which dictates efficiency of optoelectrics such as LEDs, lasers, and solar cells, is extremely low in materials with a large number of surface defects. Researchers at UC Berkeley and Lawrence Berkeley National Laboratory have developed a bis(trifluoromethane) sulfonamide (TFSI) solution for passivation/repair of surface defects in 2D transition metal dichalcogenide (TMDC). This air-stable solution-based chemical treatment provides unmatched photoluminescence QY enhancement to values near 100% without changing the surface morphology. The treatment eliminates defect-mediated non-radiative recombination, which eliminates the low performance limit of TMDC and enhances its minority carrier lifetime. This novel development can address surface passivation in numerous semiconductors which will lead to highly efficient light emitting diodes, lasers and solar cells based on 2D materials.

Worldwide photovoltaic capacity reached 178GW in 2014 and with an additional 55GW slated for deployment. With installed capacity projected to more than double by 2020, solar power is anticipated to become one of the largest sources of electricity, with solar photovoltaics representing about 16 percent of total. Current photovoltaic cell technology is based on crystalline silicon (c-Si) which generally uses doped homojunctions to create pathways of asymmetrical conductivity for electron and hole transport. This approach is limited by a host of interrelated optical, transport and recombination-based losses, most notably parasitic absorption and Auger recombination. Moreover, there are technological challenges and scaling problems associated with doping under high temperatures and with small contact fractions. To address these problems, researchers at the University of California, Berkeley, have developed advanced contact structures, which replace these doped regions, using alkali metal fluorides and metal oxides. Early lab results are reporting competitive cell efficiencies approaching 20%. These cells were fabricated using low-temperatures and no lithography, introducing potential for gains on both sides of the cost-to-performance ratio for c-Si photovoltaics.

More than a quarter of the world's carbon dioxide emissions come from burning fossil fuels to produce heat and electricity. Nuclear energy plants do not emit criteria pollutants or greenhouse gases when they generate electricity. Thermal-neutron reactors are the most common type of nuclear reactor, and light water reactors (LWRs) are the most common type of thermal-neutron reactor, which uses normal water as the primary coolant. Localized corrosion in the primary coolant circuits (PCC) is a big problem in LWRs. The rate of corrosion is often determined by certain electrochemical properties, such as the electrochemical corrosion potential (ECP), solution conductivity, temperature, pH, flow rate, and the kinetics of the reduction of a cathodic depolarizer (e.g. O2) on the surfaces external to the crack. Mechanical loading (stress intensity factor on the crack) and micro-structural/micro-chemical factors (e.g. grain size, precipitates, degree of sensitization) may also contribute to this problem. To address this problem, researchers at the University of California, Berkeley, have developed an operating protocol in which the PCC are protected over wide ranges of parameters as the reactor progresses through a fuel cycle, including: temperature, pH, ECP, solution conductivity, flow rate, and stress intensity factor. Laboratory models using Berkeley approach suggest significant LWR optimization while adding levels of safety and lowering operational costs (e.g., by avoiding primary water stress corrosion cracking in Alloy 600 steam generator tubes, which is a major corrosion phenomena in operating a PWR). In fact, Berkeley’s solutions require minimal modification to the reactor PCC, and in most cases, can be implemented with no modifications at all.

Lithium ion (Li-ion) battery technology is expected to grow to a $30B industry in the next 5 to 10 years. This growth is largely driven by the introduction of electric vehicles which reached one million plug-in electric vehicles globally in 2015. Achieving high power densities in the most energy dense battery technologies like Li-ion is a challenge because they rely on slow solid-state ion diffusion and complex chemical transformations to store high energy densities. Pure Li metal anodes have been investigated to boost battery energy density but problems remain with dendrite formation. To address these challenges, researchers at UC Berkeley are investigating metal/electrode material combinations to enhance the capacity and reversibility of hybrid battery technologies involving metal deposition. The investigators have demonstrated a unique hybrid battery cell based on metal oxide electrodes and electrolyte solution, resulting in maintained energy densities and high average areal power deliveries, whether charged for seconds or hours.

Over the last several decades, polymer membranes have shown promise for purifying various industrial gas mixtures. However, there are a number of potential applications in which highly polarizable gases (e.g., CO2, C3H6, C3H8, butenes, etc.) diminish membrane selectivities through the mechanism of plasticization. Plasticization is the swelling of polymer films in the presence of certain penetrants that results in increased permeation rates of all gases, but an unwanted, and often times, unpredictable loss in membrane efficiency. Current strategies for reducing plasticization effects often result in a reduction in membrane permeability. To address the need for plasticization-resistant membranes that retain good separation performance, researchers at UC Berkeley have developed a novel method for improving polymer membrane stability and performance upon the incorporation of metal-organic frameworks (MOFs). This method can be applied to a broad range of commercially available polymers as well as enable new polymers to be commercialized.

Hydrogen-fueled cell vehicles could gain ground as global researchers develop better processes to produce hydrogen economically from sustainable resources like solar and wind. On an energy-to-weight basis, hydrogen has nearly three times the energy content of gasoline (120 megajoule or MJ, per kilogram or kg, for hydrogen, versus 44 MJ/kg for gasoline). One problem is storing enough hydrogen on-board to achieve a reasonable driving range of 300 to 400 miles. On energy-to-volume basis, hydrogen takes up nearly three times the volume of gasoline (8 MJ/liter for cryogenic liquid hydrogen versus 32 MJ/liter for gasoline). Another problem is related to next-generation solid absorbents like metal hydrides, which typically show weakness in terms of the amount of gas that can be absorbed and delivered. To address these problems, researchers at the University of California, Berkeley, and Lawrence Berkeley National Laboratory, have developed a composite material using nanostructured metal hydrides that is capable of storing three times more hydrogen per volume at room temperature than a comparable cryogenic liquid hydrogen tank. Furthermore, low hydrogen pressures during absorbing and desorbing have been achieved. This represents a significant economic and safety advantage over technologically complex and costly high-pressure (10,000 psi) hydrogen tanks commonly used in mobile hydrogen storage applications today.

Thermochemical cycles combine heat sources with chemical reactions. Energy production from thermochemical cycles are quickly evolving as global researchers develop better processes to generate electricity from sustainable yet intermittent resources like solar. Typical thermochemical processes generate chemical reactants for thermochemical storage. One problem is with efficiency, where these chemical reactants are merely burned together again to recreate heat, which is then converted into mechanical energy that is subsequently converted into electrical energy. Another problem relates to flexibility, in terms of being limited to hydrogen and oxygen as the chemical reactants. To address these problems, researchers at the University of California, Berkeley, are developing a generalized closed-cycle thermoelectrochemical framework with expected chemical conversion efficiencies above 80% and high overall system efficiencies using innovative combined-cycle design.

As the most reducing and lightest metal, lithium is a desirable battery anode material due to its abilities to yield a high cell voltage and a high specific energy capacity. Lithium ion (Li-ion) battery technology is expected to grow to a $30B industry in the next 5 to 10 years. This growth is largely driven by the introduction of electric vehicles which reached one million plug-in electric vehicles globally in 2015. Problems with Li electrodes have been investigated and challenges remain, including dendrite growth, flammability of organic solvents, and decomposition of the anions at the electrode. To address these challenges, researchers at UC Berkeley are developing single-ion, solid polymer electrolytes as replacements for liquid electrolytes. The investigators have demonstrated a solid-state battery system which uses single-ion conduction and leverages three-dimensional connectivity of polymer networks to provide superior mechanical strength and flexibility which affects bulk conductivity.

Nearly all hydrocarbons are generated from petroleum or natural gas processing. Hydrocarbon mixtures are separated into component fractions at scale for the commercial production of fuels and chemical feedstocks. These large-scale systems use a lot of energy and require many sub-systems with expensive adsorbents or membrane materials like zeolites, polymers, metal oxides, and carbon. Since many of these hydrocarbon mixtures have molecules with similar structures, properties, and reactivities, many of the technical challenges and associated high costs remain. Metal-organic frameworks (MOFs) hold promise for efficient and complex separations based on their desirable surface areas, tunable pore geometries, and adjustable surface functionality. To help align MOFs with challenges in hydrocarbon separations, researchers at UC Berkeley have developed thermally robust and tunable MOF materials which are capable of separating mixtures of saturated, unsaturated, and aromatic hydrocarbons. The researchers have demonstrated the purification of a four component gas-phase mixture. 

Conventional power conversion cycles which turn fuel into heat and heat into power are constrained by basic thermodynamic considerations. The most modern technologies have been limited to 60% even with multiple cycles combined (i.e. Brayton and Rankine combined cycle). Recent demonstrations have shown relative efficiency gains of 30% in both spark-ignited and compression-ignited regimes. Researchers at the University of California, Berkeley, are working to outdo these efforts by working on an ultra-high efficiency power cycle framework using argon as the working fluid. Early laboratory results suggest the argon engine could easily achieve 70% or greater thermal efficiency. Under such research the argon replaces nitrogen as the working fluid and is recycled in the closed-loop system.

There are many applications that require the storage of a high density of gas molecules. The driving range of vehicles powered by natural gas or hydrogen, for instance, is determined by the maximum density of gas that can be stored inside a fuel tank and delivered to the engine or fuel cell. In certain situations, it is desirable to lower the pressure or raise the temperature needed to store a given amount of gas through the use of an adsorbent. Developments in next-generation adsorbents, such as metal-organic frameworks and activated carbons, have shown certain weaknesses in terms of the amount of gas that can be delivered when an application has a minimum desorption pressure greater than zero and when a significant amount of heat is released during adsorption or cooling occurs during desorption. To help solve these problems, researchers at the University of California, Berkeley, have developed a next generation of materials using novel porous metal-organic frameworks that demonstrate unprecedented deliverable gas capacities. These engineered adsorbents maximize the amount of gas delivered during each adsorption/desorption cycle. This shows promise in developing next generation gas storage materials for applications with a wide range of operating conditions.

The rapid expansion of data-intensive information technology has highlighted the urgent need for a successor to the silicon based complementary metal-oxide-semiconductor (CMOS) integrated circuit (IC) architecture to continuously improve the performance of digital data management. Over the last decade, the evolution of scaling of dimensions, energy efficiency, and processor speed has slowed significantly due to the limitations imposed by a photolithographic top-down approach and the limited control of inorganic semiconductor material properties at sub-10nm dimensions. Carbon-based low-dimensional materials may aid problems with transistor scaling, speed, and energy efficiency for future IC generations. To help address these needs, researchers at the University of California, Berkeley, have developed unique heterostructures based on innovative graphene nanoribbon (GNR)-based materials and methods. These structures are chemically synthesized from the bottom up using rational polymerization methods, producing GNRs with uniform sub-5nm widths and with atomically precise edges. This approach shows promise towards producing GNRs of identical molecular structure in bulk.

In recent years there has been a greater interest in making more energy efficient automobiles.  A number of plug-in vehicles (PEVs) or hybrid electric vehicles (HEVs) are offered by nearly every automaker today.  Although these vehicles offer a cleaner and more energy efficient alternative to traditional petroleum-fueled vehicles, mainstream consumer acceptance of these technologies is stymied by considerations of their premium price, limited travel range, and extended charging times, all consequences of current battery technologies. To address these problems, UC Berkeley researchers have developed an electro-mechanical flywheel system to be incorporated into PEVs and HEVs which increases efficiency, extends battery life and extends travel range making this battery/flywheel system more cost effective and more appealing to the mainstream consumer.  The system combines the chemical energy storage in a battery with the electro-mechanical energy storage in a flywheel to provide the system with both high power capability and high energy density.   

Supercapacitors are attractive energy storage devices due to their high-power capabilities and robust cycle lifetimes.   “Super” capacitors are named in part because the electrodes are composed of materials with high specific surface area and the distance between the electrode and electrochemical double layer is very small compared to standard capacitors.  A variety of porous silicon nanowires have been developed for use as supercapacitors electrodes by maximizing the specific surface area of active materials.  Although the use of Si is attractive due to its wide-spread adoption by microelectronics industry and due to its abundance, Si nanowires are highly reactive and dissolve rapidly when exposed to mild saline solutions.  Previously, silicon carbide thin films were used to protect the porous silicon nanowires, but the coatings were 10’s of nm thick and while they successfully mitigated Si degradation during electrochemical cycling in aqueous electrolytes, they also resulted in pore blockage and a large decrease in energy storage potential.   Researchers at UC Berkeley have developed methods and materials to improve porous silicon nanowires by overcoming the above limitations.  The resulting nanowires have an ultrathin carbon coating preserving the pore structure while mitigating Si degradation.  The resulting supercapacitor electrodes have the highest capacitance (and hence energy storage) per projected area to date.   

Generating fuel and chemicals from the photosynthesis of cyanobacteria has great potential – especially in comparison to other approaches to producing biofuels. However, improving the efficiency of the cyanobacteria photosynthetic process is necessary to lowering the production costs of the resulting biofuel – so that it is more cost-competitive with conventional fuels. To address this opportunity, researchers at the University of California, Berkeley have developed a novel approach to improving the photosynthetic efficiency of cyanobacteria. This Berkeley innovation is based on minimizing the phycobilisome light-harvesting antenna, and it has shown an increase in the saturation of photosynthesis by a factor of about two. This increase in efficiency in a population of cells would decrease the cost associated with producing isoprene, beta-phellandrene, and other chemicals from cyanobacteria photosynthesis.

Thermophotovoltaics (TPVs) converts infrared rays from a very hot thermal source into photovoltaic electricity. This process is analogous to using solar cells, but TPVs use thermal emitter and a photovoltaic diode cell to change energy forms. Conventional silicon solar cell is effectively a TPV device in which the sun functions as the emitter, and the cell’s silicon structures absorb in the visible portion of the spectrum. Many solar cell systems neglect the small infrared photon emissions due to known physical and design constraints. Thermophotovoltaic devices are uniquely positioned to overcome that limitation by harvesting the unconverted thermal-infrared emissions. Historically, the efficiency for such devices (with spectral selectivity) reach only 15%. For a world with increasing energy and conservation needs, a thermophotovoltaic module solution would need to perform at higher efficiencies for a variety of high- and low-power demand scenarios. To address these problems, researchers at the University of California, Berkeley, have developed the "Regenerative Thermophotovoltaics" framework which is designed to exploit the small infrared photons typically lost in thermophotovoltaic cells, while architecting the device for optimal variable-demand performance. The Berkeley device framework effectively captures and recycles unused photons in the photovoltaic cell that are generally below ~0.8eV energy. By putting these thermal-infrared photons to work, conversion efficiencies >50% may be produced, which could contend with conventional internal combustion engine (ICE) approaches. 

Discovering new rechargeable battery materials and systems are of considerable technological importance because of the increasing demands for reliable energy storage, from electric vehicles (EVs) and backup power systems to implantable medical devices and better consumer electronics. The lithium-sulfur (Li/S) chemistry is a potential breakthrough solution to this enduring battery performance problem. An Li/S battery could achieve specific energy levels up to 800 Wh/kg, while lithium-ion cells today delivery only 250 Watt-hours per kilogram (Wh/kg), with potential improvement to 400 Wh/kg in the future. EVs use today’s state-of-the-art lithium-ion battery cells, yet the batteries are still the weakest link in determining the vehicle’s performance, durability, and cost. To help achieve a better Li/S battery, researchers at UC Berkeley have devised novel carbon-coated materials and methods which show promising specific capacities and stable cycling performance, with a high initial discharge capacity. This innovation may help to overcome the electrode challenges that has previously prevented the adoption of the lithium-sulfur cell.

The selective and efficient conversion of light alkanes into value-added chemicals remains a challenge for those in the petrochemical and chemical industries.  Currently, there is no go-to commercial process for the selective oxidative conversion of C1-C3 hydrocarbons into value-added chemical feedstocks, such as methanol and ethanol. Industrially, methanol is produced in an indirect and energy intensive process beginning with the steam reformation of natural gas into synthesis gas. After fermentation, ethanol is largely produced from the hydration of ethylene/ethene, which relies on the use of concentrated acids and elevates risk for human safety and environment. To overcome these challenges, researchers at UC Berkeley have devised novel materials and methods involving redox-active metals within porous metal-organic frameworks for driving improved catalytic oxidation of small hydrocarbons to their corresponding alcohols and aldehydes. This innovation could be of special importance to the boom of shale gas processing, which consists of largely methane, but also contains large amounts of ethane and other light alkane impurities.

Berkeley researchers have created an electric fan with visual detection camera and movement recognition software to identify the presence and location of occupants. Occupant tracking algorithm localizes air movements to individualize comfort and conserve energy. The fan can be integrated in ceilings, wall partitions or office furniture.

Metal-organic frameworks (MOFs) are porous crystalline nano-materials that are constructed by linking metal clusters called Secondary Building Units (SBUs) and organic linking ligands. This case provides MOFs which comprise a plurality of SBUs comprising different metals or metal ions and/or a plurality of organic linking moieties comprising different functional groups.

Nickel oxide (NiO) films have been deposited by sputtering, thermal evaporation, chemical vapor deposition, pulsed laser deposition or electrochemical deposition which require either a high vacuum chamber or high energy consuming procedures and have limitations in substrate selection. Similarly, nickel (Ni) films have been deposited by sputtering, pulsed laser deposition, and atomic layer deposition, which require either a high vacuum chamber or have limitations in substrate selection. To help solve these challenges, researchers at Berkeley have successfully demonstrated new techniques for producing NiO nanoparticle solutions under ambient conditions. Early results suggest promising microstructural and electrical characteristics. The new compositions and structures may have broad applications from advanced semiconductor products to energy production and storage.

Thermal discomfort is a prevalent complaint from occupants in shared workspaces and public buildings. Personal comfort systems (PCS) create local environments for individuals that are perceived as comfortable across a broad range of ambient space. Implementing PCS systems in a building can save up to 30% of an average building’s total HVAC energy. As building owners and residential consumers become more aware of the potential energy bill savings of individual room thermal systems, spot heating and cooling is increasingly relied upon.  Berkeley researchers have taken this further by developing a rechargeable chair, which consists of mesh seating coverage, reflective surfaces, air plenum chambers and spot heating functionality. The technology exploits the concept of alliesthesia operating spatially across the skin surface. Localized resistance heating is woven into the mesh fabric in key contact areas in the seat and back. Radiant heat loss from the body to the environment is redirected to conserve energy. Cooling of the body is achieved by increasing convective heat and moisture exchange across the underside and backside surfaces of the mesh. This contrasts sharply with traditional ventilation approaches that pushes or pulls air through the seat surface. Comfort conditions can be maintained for individual users occupying the same space between 60.5 and 82.5 F. The battery-powered chair has a 4-day operation capacity and switches off when unoccupied.  

Measuring the flow rate and direction of gas flow in natural gas pipelines is of interest to both the management of gas delivery systems and the determination of consumer usage and payment. To improve on methods for measuring gas-flow rate and direction, researchers at UC Berkeley have developed microfabricated, ultrasonic gas-flow sensors. These innovative sensors are inexpensive, small and have modest power requirements -- making them suitable for wireless implementation. Moreover, these sensors can be mounted so that they don't intrude within the inner surface of a pipe, and therefore don't impede the conventional use of pipe cleaning (pigs) that fill the diameter of pipes.