Metals Tech

The world’s first rechargeable proton battery has been created and demonstrated by a team of researchers in Australia. The current battery, which is now just a prototype to prove that the mechanism works, is a big step towards a more environmentally sound energy storage system.

Unlike current lithium-ion designs that use rare materials, the prototype battery uses carbon and water to store electrical charge. The proof-of-concept was created by a team at the RMIT University in Melbourne, Australia, as announced by the university on social media on Wednesday, March 7.

“Carbon, which is the primary resource used in our proton battery, is abundant and cheap compared to both metal hydrogen-storage alloys and the lithium needed for rechargeable lithium-ion batteries,” lead researcher Professor John Andrews explained to Fairfax Media via The Age Australia.

With the world now rapidly moving towards electric-based transportation, there is now a need to come up with rechargeable batteries that are more environment-friendly to produce and dispose of.

“Our latest advance is a crucial step towards cheap, sustainable proton batteries that can help meet our future energy needs without further damaging our already fragile environment,” Andrews noted.

Andrews and his team are now working to improve the capacity of the proton battery, which works by having the carbon at the battery terminals taking up the protons released when the water is split into Hydrogen and Oxygen ions during charging.

During discharge, the positively-charged Hydrogen atoms, which are basically protons in this state, return to a reversible fuel cell to combine with oxygen from the surrounding air to re-form into water. The entire process produces no emissions, too.

Professor Andrews estimates that the proton battery could be commercially viable within five to ten years, and has the potential to compete with the Tesla Powerwall or even bigger applications.

The power company, which recently placed bids to build the largest battery energy storage project in the world, has connected a 74.5 MW PV project with a 10 MW/40 MWh storage facility, in the United States.

NextEra is one of the world’s largest owners of renewable energy, and they’re taking steps to be in the same position in the energy storage market. The company was recently discovered, per a tip from one of pv magazine’s readers, to be behind the largest energy storage bids yet received globally – and now they’re announcing the nation’s largest solar+battery storage project connected to the power grid.

FPL, a NextEra subsidiary that serves 50% of the Florida electricity market, has connected a DC-coupled 10MW/40MWh battery to their 74.5 MW-AC Babcock Ranch Solar Energy Center. The solar park is located on 440 acres in central Florida and is being built in a partnership with the Babcock Ranch – a 100% renewable powered development..

The factsheet for the Babcock Solar Ranch can be found here(PDF).

The energy storage project, on its own, is not the largest in the United States. Currently, a 100 MWh project in Southern California Edison territory holds that honor. Other solar+storage projects that are larger have been announced. Among these, TEP announced record-setting pricing with a 100 MW solar + 30 MW/120 MW energy storage project.

The solar plant is part of a series of 74.5 MW solar plants being built to serve the Florida market. The plants are being built under the moniker of ‘Sanctuary Solar’, with support from the Audubon Society. The sites of these facility are being designed to allow a significant amount of the land to be planted with native grasses, trees, shrubs and vines. Plants are being chosen to provide food for birds and pollinators. Quality wetlands are being preserved, which also provide habitat for birds.

Panasonic Corporation has begun mass production of prismatic-type automotive lithium-ion batteries at its factory in Dalian, China, and held a ceremony to mark the first shipment on Monday.

The market for eco-conscious vehicles, including hybrids, plug-in hybrids, and electric vehicles, is growing every year thanks to the increase in environmental awareness in recent years. To respond to the market demand, Panasonic has been gearing up to start production at this factory, which is its first production site for prismatic-type automotive lithium-ion batteries in China.

Amidst expectations of expanding demand for automotive lithium-ion batteries, Panasonic manufactures high-capacity and high-safety prismatic-type batteries at this factory and ships them to the North American and Chinese markets. Shipments will be expanded in the future to reach more destinations, helping to drive the spread of eco-conscious vehicles.

With the beginning of mass production shipments of automobile lithium-ion batteries from this factory, Panasonic now has a production system covering Japan, United States, and China, three key global locations.

By strengthening the global competitiveness of its automotive batteries with these sites, Panasonic will further expand its automobile battery business in the future.

Lithium ion batteries are a leading energy storage technology for electronic portable devices and hybrid electric vehicles. Simultaneous characterization of the structure, chemical composition and elemental distribution in Li-ion battery materials can reveal the relationship between Li-ion transport, structural effects (phase transformation, internal stress), and battery performance and its degradation.

A long-standing challenge to understand Li-ion transport is based on the fact that this light atom cannot be detected using direct X-ray techniques (EDX, XRD and XAS) due to its weak scattering and emission properties. Nanoscale mapping can be achieved by multi-modal correlative microscopy which combines focused ion beam scanning electron microscopy (FIB-SEM), energy dispersive X-ray spectrometry (EDX) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), as shown in figure 1.

The focused ion beam (FIB) is used to prepare a fresh cross-section of the battery under vacuum conditions which facilitates its direct, in-situ analysis without exposure to the atmosphere.

Figure 1: FIB cross-sections of a Li-ion battery electrode

3D Structural Analysis using FIB-SEM Tomography

Nano-structural changes in the electrodes that occur during charging-discharging cycles are among one of the most problematic degradation processes in Li-ion batteries. The mechanisms by which nano-degradation occurs are complex, involving multiple pathways. A lack of understanding of degradation processes represents a significant barrier towards the development of enhanced lithium-ion battery systems.

Degradation within the electrode can be observed using an FIB-SEM system such as the LYRA3 from Tescan. The FIB is used to mill the surface of the electrode to expose cross sections, which are then imaged via SEM to give images such as figure 1. This process is then continued layer by layer and the captured SEM images are stacked together to form an overall 3D image of the electrodes internal structure. By using FIB-SEM researchers can therefore create a 3D reconstruction of the electrode within a resolution of a few nanometers.

This visual reconstruction can be carried out on electrodes at different points in their charging lifecycle, allowing researchers to visualize the structural changes that occur over a lithium ion batteries lifetime. Figure 2 demonstrates the effect that an increasing number of charging cycles has on electrode morphology.

Figure 2: 3D reconstructions of electrodes at various cycling stages in terms of active particles (left), porosity with carbon black (middle) and phase interfaces (right). Courtesy of Dr. Bohang Song, University of Oxford

The cross sections taken by FIB-SEM (figure 1) are of a high enough resolution to determine the size of lithium based particles (consisting of Li(Li_0.2Mn_0.54Ni_0.13Co_0.13)O₂) within the electrode. It is these particles that lithiate and delithiate during charge/discharge cycles, allowing the electrochemical cell to function. Measuring the size distribution of lithium particles in the electrode as the number of charging cycles increases provides insight into the mechanisms by which electrode degradation occurs.

It can be observed that the number density of ‘small’ (sub 200 nm) lithium particles increases as the number of charging cycles increases, confirming the fragmentation of the electrode. The 3D image provided by FIB-SEM indicates that fragmentation occurs more rapidly at the electrode-electrolyte interface – which confirms that degradation is linked to the lithiation/delithiation processes that occur during a charge/discharge cycle.

To understand the processes occurring within the particles which result in fragmentation, specific particles within the electrode can also be observed over the course of the experiment. The SEM images taken can be used to create nano-tomographic reconstructions of the particles.

These reconstructions show that many electrode particles contain small internal voids before any cycling has taken place, these are thought to be a direct result of the sintering process by which the electrode is formed. Over successive charging cycles the volume of these voids increases as the electrode degrades and ‘secondary particles’ break away.

SEM imaging of secondary particles allows researchers to observe that they have sharp, crystalline edges. This supports the conclusion that their shape is the result of compaction of lithium material during electrode formation, rather than the result of electrochemical grinding.

The information gathered by FIB-SEM on the distribution of degradation throughout the electrode and the increase in small particle density provides valuable information on battery behavior. Additionally, insights into the mechanisms of lithium-ion battery degradation, such as void growth and secondary particle formation, and how these could be linked to electrode formation processes can be used to design new, more effective processes of electrode formation.

EDX Analysis

EDX is the most common elemental mapping technique readily accessed in the SEM. EDX can be used to provide an elemental map of a samples surface, as shown in figure 3. However, a significant limitation of the performance of routine EDX is a low sensitivity to light elements (lighter than C) and almost no sensitivity to Li, which gives only weak scattering and low emissions.

This means that for lithium battery analysis EDX must be used alongside a technique which is sensitive towards lithium.

Figure 3: An EDX spectrum and elemental mapping of a Li-ion battery electrode

Supplementing EDX with TOF-SIMS

In contrast to EDX, TOF-SIMS is sensitive to lithium ions, as demonstrated in the mass spectra shown in figure 4, making it an attractive candidate for use in Li-ion battery research. TOF-SIMS allows changes in lithium distribution within a batteries internal structure to observed over the lifetime of the battery, which, as in the previous case study above, can be used to determine relationships between battery structure and performance.

Figure 4: TOF-SIMS spectrum of a Li-ion battery electrode following 15 charging cycles, the main isotope Li ion peak ( 7 m/Q) is clearly visible.

The LYRA3 from Tescan can be equipped alongside an EDX system and TOF-SIMS analyzer to provide a full elemental map of a battery surface. The FIB from the LYRA3 can be used to ablate secondary ions from the battery materials surface, which can then be analyzed using TOF-MS. This data can be integrated with elemental data from EDX to provide an elemental map as in figure 3.

In addition to the creation of qualitative maps of Li distribution, TOF-SIMS enables quantitative analysis of the elements present. This allows the presence of phenomena such as trapped lithium in the battery material to be objectively quantified. Trapped lithium, where the ions are immobilized and unavailable for charge cycles, is a symptom of battery degradation.

TOF-SIMs imaging of battery surfaces shows that lithium trapping is a result of both grain boundaries and internal voids within the electrode. These structural features create barriers within the electrode, preventing the electrolyte access to regions of the electrode, rendering the lithium in these regions as useless. The extent of trapped lithium can be observed in the difference between the discharged and charged FIB secondary electron images, superimposed on a TOF-SIMS map, in figure 5.

Comparison of the Li concentration in fully charged and fully discharged battery electrodes can also be seen in figure 5.

Figure 5: FIB secondary electron images with normalized elemental distribution maps of Li (7) are shown for fully dscharged (top row) and fully charged (bottom row) samples. The full field of view is 8 μm

Tata Motors is developing an EV Battery Pack for the future of its lineup. Tata recently showcased their EVision concept with a new architecture. This new architecture can be used in various electric vehicle applications by making changes to just its underbody.

Tata Motors CEO and MD Guenter Butschek told Autocar that the EVision was a ‘proof of concept’ for various considerations including battery tech. The battery pack on the EVision is a cylindrical-cell lithium-ion, the same technology as seen on electric carmakers Tesla.

Tata Motors mentioned that their new EV battery packs will provide a range of over 300 km on a full charge. The under-development EV battery packs will be space-efficient, liquid-cooled cylindrical packs. Mr Butschek also mentioned that going at the current rate of development, they could achieve a range of 400 km as well.

Tata Motors believes that the higher range will help eradicate any ‘range anxiety’ even under Indian driving conditions. The high range if achieved, will put Tata Motors’ EV battery pack on par with other European EVs. The competition for the future Tata EVs includes the Nissan Leaf and the Hyundai Kona electric.

Tata recently showcased the electric variants of the Tigor and the Tiago models at the Auto Expo 2018. Though none of them has made it to the market yet, delivery of 10,000 units has already commenced to a Government-owned entity – Energy Efficiency Service Limited.

DriveSpark’s Thoughts On The Development of The EV Battery Packs By Tata Motors’

It is safe to say, Tata Motors is concentrating on EVs for the future. With TataMotors EV battery packs under development, It is only a matter of time until Tata Motors introduces these technologies in the Indian market.