Lithium-ion Chemistries Research Articles

Throwing down the Gauntlet

In a recent issue of the Journal of the Electrochemical Society, Dahn and coworkers set the standard not only for the performance level that batteries should strive to achieve but also for how batteries should be tested.

Li+ -Containing, Continuous Silica Nanofibers for High Li+ Conductivity in Composite Polymer Electrolyte.

Solid-state electrolytes have recently attracted significant attention toward safe and high-energy lithium chemistries. In particular, polyethylene oxide (PEO)-based composite polymer electrolytes (CPEs) have shown outstanding mechanical flexibility and manufacturing feasibility. However, their limited ionic conductivity, poor electrochemical stability, and insufficient mechanical strength are yet to be addressed. In this work, a novel CPE supported by Li+ -containing SiO2 nanofibers is developed. The nanofibers are obtained via sol-gel electrospinning, during which lithium sulfate is in situ introduced into the nanofibers. The uniform doping of Li2 SO4 in SiO2 nanofibers increases the Li+ conductivity of SiO2 , generates mesopores on the surface of SiO2 nanofibers, and improves the wettability between SiO2 and PEO. As a result, the obtained SiO2 /Li2 SO4 /PEO CPE yields high Li+ conductivity (1.3 × 10-4 S cm-1 at 60 °C, ≈4.9 times the Li2 SO4 -free CPE) and electrochemical stability. Furthermore, the all-solid-state LiFePO4 -Li full cell demonstrates stable cycling with high capacities (over 80 mAh g-1 , 50 cycles at C/2 at 60 °C). The Li+ -containing mesoporous SiO2 nanofibers show great potential as the filler for CPEs. Similar methods can be used to incorporate Li salts into other filler materials for CPEs.

Next Generation Materials for Lithium-Ion Space Batteries

EaglePicher has been supplying batteries for energy storage for satellites and other space applications since 1958. These batteries have achieved over 2.6 billion hours of cell operations with no failures in orbit. Over the decades the battery chemistry has changed amongst various chemistries with some overlap and some still being used today. Typical space battery chemistries include: silver-zinc, nickel-hydrogen, nickel-cadmium, and then lithium-ion. Even within the lithium-ion chemistry the formulations and packaging has evolved over time and continues to change. Lithium-ion space batteries continue to evolve today. New satellites and space applications are demanding increased energy, more power, and smaller volumes. This has led to improvements in increased energy, wider operating temperatures, more power and smaller packages. Every change in battery performance requires new or modified battery materials. For increased energy the incumbent cathode material for lithium-ion batteries is Lithiated Nickel Cobalt Oxide (NCO). This was changed to the Lithiated Nickel Cobalt Aluminum Oxide to increase the energy and improve cycle life. For wider operating temperatures the electrolyte formulation has evolved with new components and additives. Newer and next generation satellites are carrying state of the art instruments that demand high power or pulses of power. New lithium-ion battery chemistries have been developed to supply very high power discharges to supply the large currents. As small satellites are increasing in popularity, there is a push for smaller battery packs. This has led to a decrease in cell capacity and the introduction of commercial of the shelf (COTS) cells. These are often cylindrical in shape and typically 18650 in size. Transitioning to COTS cells has increased the ability to create modular space batteries, but has brought up new concerns on quality and reliability. Quality and reliability, plus safety, are top concerns for space batteries. Replacement of batteries in space is extremely difficult and expensive. As each of the next generation battery materials are developed, reliability and safety much be eminent. These materials and batteries are often expected to supply power for decades. The continued testing, evaluation and analysis of the new chemistries and designs provides assurances for long-term performance and reliability. As these batteries have the potential to power satellites, landers, rovers, capsules, and habitats, EaglePicher continues to develop, evolve, demonstrate, and produce new battery chemistries and designs to meet the mission requirements. Acknowledgements We would like to thank: NASA JPL, Lockheed Martin and the Unites States Government for supporting some of this effort, and many of the EaglePicher employees who worked on these projects.

Deciphering the Structure-Property Relationship in Sulfide-Based Solid Electrolytes for All-Solid-State Na-Ion Batteries

Safety concerns on conventional lithium ion batteries are attracting a lot of attention from both academia and industry with the rapid growth of the electric automobile market. Replacing flammable organic liquid electrolytes with nonflammable inorganic solid electrolytes can potentially eliminate the fire hazards. On the other hand, low-cost electrochemical energy storage technologies beyond lithium chemistry are also highly desired for large-scale energy storage applications. All-solid-state Na ion batteries are one of the promising candidates for grid-level energy storage owing to their low cost and outstanding safety properties. The key enabler of this technology is solid electrolyte with sufficiently high ionic conductivity at room temperature and good electrochemical stability. This work presents a group of novel sodium superionic conductors to address the foregoing issues, which is a topic currently receiving extensive attention in the field of electrochemistry and energy storage. Through a rational design approach and with using facile solid-state reactions, a series of novel Na4SnS4-Na3SbS4 solid-solution-based compounds with cation and anion substitutions were obtained. These sulfides show room temperature conductivities of 0.1~1 mS/cm, which is among the highest values reported for sodium ion conductors to date. The underlying structural factors, including lattice parameters, concentration of defects, local ordering, etc., of these compounds are investigated with a variety of characterization methods, including synchrotron X-ray diffraction, neutron diffraction, and pair distribution function analysis. Interesting structure-property relationships in these compounds were revealed. All-solid-state Na-ion battery cells using these as-synthesized materials as electrolyte was successfully assembled and cycled, demonstrating the promise of this group of sulfide-based compounds as solid electrolytes and implying new opportunities for materials and device development in solid-state batteries.

Ion Tracking in Aqueous Sodium-Ion Batteries

An energy economy based on renewable technologies will need energy storage capabilities on an enormous scale to combat power generation fluctuations. To provide the amount of energy storage that will be needed, low-cost batteries made with earth abundant elements will be a necessity for grid-scale storage. Furthermore, these batteries should have chemistries that can guarantee safety for the users and be non-toxic to the environment. Aqueous sodium-ion batteries (ASIB) are one option that can fill these requirements while also promising long lifetimes. There has been considerable effort put forth into the development of sodium ion intercalation batteries that combine sodium and lithium chemistries. Sodium titanium phosphate (NTP) as the anode and lithium manganese oxide (LMO) as the cathode are a commonly researched pairing. While the LMO is only capable of cycling the lithium ions in solution, the NTP is capable of cycling both sodium and lithium ions, although to different degrees at different potentials. This talk will look into the conditions at which the different ions cycle into the NTP, how this can turn sodium titanium phosphate into lithium titanium phosphate (LTP), as well as the effect that lithium insertion into NTP has on the LMO cathode. This will be done by tracking ionic concentrations in laboratory scale batteries at different states-of-charge (SOC’s) and states-of-health (SOH) and correlating to differential capacity curves. Comparisons will be made against ex-situ cyclic voltammetry studies for NTP and LTP when these materials are exposed to different ratios of Li+ and Na+ in solution.

Insights from incorporating reference electrodes in symmetric lithium-ion cells with layered oxide or graphite electrodes

Symmetric cells provide complementary means to probe electrochemical processes in lithium-ion batteries. Here, positive and negative electrodes harvested from conventional oxide/graphite cells are cross-paired, and the assembled reference-electrode-bearing symmetric cells are cycled/aged. For graphite symmetric cells, the electrode potentials and impedances remain nearly constant during calendar aging and the parasitic currents are typically small. However, at higher cell voltages when the “positive” graphite potential exceeds 1.0 V vs. Li/Li+, the capacity loss is higher, indicating that even a mild (but prolonged) overdischarge can damage the SEI. For the layered-oxide symmetric cells there are strong parasitic currents and a persistent slide of the electrode potential over time during calendar aging. Significant cell impedance rise, especially at higher hold voltages, is also observed. Curiously, the impedance rise in the “negative” oxide electrode, which experiences potentials below 4.0 V vs. Li/Li+, is greater than in the “positive” oxide electrode that experiences much higher potentials. We postulate that electrolyte oxidation is responsible for the behavior of these oxide symmetric cells, as it supplies electrons (that bind more Li+ into the cathode, causing the potential slide) and protons (that contribute to impedance rise). These insights can guide the development of future lithium-ion cell chemistries.

Thermal Runaway Suppression Capability of State-of-the-Art Coolant Fluids for Lithium-Ion Battery Applications

With the increasing market uptake of hybrid/electric vehicles, along with growing electrification of transportation, battery safety is under worldwide scrutiny. Lithium-ion chemistries have become popular amongst battery manufacturers due to their superior performance and lifetime compared to lead-acid/nickel-metal-hydride based chemistries. However, due to the nature of the materials and their potential exothermic reactions, lithium-ion cells possess a high risk of thermal runaway related hazards. In this study we aim to investigate how aftermath of a thermal runway can be suppressed by employing coolant fluid. Experiments were conducted to investigate the viability of various coolant fluids as thermal runaway suppressants under external heating abuse conditions; on lithium-ion cells. The test apparatus (see attached image file – figure 1) was half filled with a coolant fluid and a 21700-type cylindrical cell at 100% state of charge (SOC), held vertically, such that half the cell was submerged. An external heating setup was employed via nichrome based special heating elements on the non-submerged half of the cell. The cell was heated with a known power value. Two types of cooling fluid were trialled using identical test set-ups, and 9 experiments were conducted in the following categories: 3 control (no fluid), 3 boiling fluid (having low boiling point in range of 70 to 80 °C) and 3 dielectric oil. There were 3 thermocouples attached to the surface of the cell (1 closer to the positive tab, 1 near the geometric centre, 1 closer to the negative tab). Another 3 K-type thermocouples with range till 1300 °C and accuracy of ±2 °C were employed to measure cell surrounding temperature, i.e. on the pressure cap present on the positive side of the cell, in the coolant fluid and another thermocouple in the air on the likely cell venting path. In the control experiments, the cells initially became internally short-circuited, then, their current interrupt devices (CIDs) were triggered and the cells eventually went into thermal runaway (see attached image file – figure 2). Temperatures in the order of 1100 °C were recorded. In the boiling fluid experiments, there was an order of magnitude increase in the duration to internal short-circuiting compared to no fluid (order of 1000 seconds compared to 100 seconds for control test cases) and the CID of every cell was partially triggered (see attached image file – figure 3). Some of the cells did not undergo thermal runaway. In those cases, temperatures up to 187.7 °C was observed. However, 1 cell went into full thermal runaway with the CID being fully triggered (temperatures up to 394.3 °C was observed). Throughout all the boiling fluid tests, the volume of fluid reduced continually. This might be detrimental to the usability of the fluid as a thermal runaway suppressant in case of longer duration experiments. In the dielectric oil experiments, the time to internal short-circuiting was similar to the boiling fluid and the CID was not triggered on any of the cells. No cells underwent thermal runaway and maximum cell surface temperatures were in the region of 160 °C. Throughout all the dielectric oil experiments, the volume of fluid remained constant. It was observed that both the boiling fluid and dielectric oil have strong potential as thermal runaway suppressants, with the dielectric oil completely preventing thermal runaway in any of the tested cells. This is despite the cell only being half submerged in fluid. A cooling/safety system centred on these types of fluids could manifest, perhaps as permanently submerged battery packs, for hybrid/EV automotive, aerospace and rail applications. One potential drawback for the deployment of fully submerged systems is the additional weight required. This could be mitigated in a number of ways, one being the integration of suppressant fluids into current cooling systems. It should be also noted that the time taken to internal short circuit was longer for the cases where boiling fluid was employed compared to where dielectric oil. However, in one of the cases, where boiling fluid was employed, the cell went into full thermal runaway. This could be due to the low boiling point and high volatility of the boiling fluid which makes it unreliable in an open system. In further work, cells connected in serial strings will be considered under further thermal safety scenarios. Along with Fourier-Transform Infrared Spectroscopy (FTIR) based gas analysis to investigate the effect of various failure modes such as nail penetration, overcharge, external heating on the gas generation at different SOCs and heating rates in submerged environment. Figure 1

New Electrode Materials for Sodium Ion Batteries

Sodium-ion batteries (SIBs) are evolving as a low-cost alternative to the state-of-the-art lithium-ion batteries (LIBs). Elementary properties of sodium, high abundance and low cost associated with sodium precursors made it a realistic alternative to lithium-ion chemistry [1, 2]. Research activities on SIBs are growing worldwide and still require a great deal of basic research. Currently, the research on SIBs is focused on the development of new cathode and anode materials or combinations with improved properties such as high energy density, sustainability, and safety. Sodium insertion in hard carbon is strongly debated, and a full and consistent picture of the underlying mechanism is still missing. By combining in-situ Raman spectra obtained during sodium insertion in hard carbon with detailed ab initio studies, for the first time we provide a complete description of the Na insertion process in hard carbon [3]. On the cathode side, we propose weberite-type sodium metal fluorides (SMF), a new class of high voltage and high energy density materials which are so far unexplored as cathode materials for SIBs [4]. Weberite-type is highly favorable for sodium-containing transition metal fluorides, with a large variety of transition metal combinations (M, M’) adopting the corresponding Na2MM’F7 structure. A series of known and hypothetical compounds with weberite-type structure were computationally investigated to evaluate their potential as cathode materials for SIBs. Weberite-type SMFs show quasi-three-dimensional pathways for Na+ diffusion with surprisingly low activation barriers. The high energy density combined with low diffusion barriers for Na+ makes this type of compounds promising candidates for cathode materials in SIBs. We also present the synthesis and electrochemical properties of new sodium vanadium oxy phosphate (NaVOP), Na2+xV3P2O13 (0 ≤ x ≤ 2). NaVOP shows a reversible capacity of 150 mAh g-1 at an average voltage of 2.5 V vs. Na/Na+, with high cycling stability [5]. The post-structural analysis shows Na2+xV3P2O13 (0 ≤ x ≤ 2) is structurally stable over a wide range of sodium extraction and reinsertion demonstrating its potential as cathode material for SIBs.

Tractable lithium-ion storage models for optimizing energy systems

Model-based optimization of energy systems with batteries requires a battery model that is accurate, tractable, and easy to calibrate. Developing such a model is challenging because electrochemical batteries exhibit complex behaviours. In this paper, we propose and evaluate a family of battery models that have different trade-offs between accuracy and complexity. We derive our models from a recently developed battery model, which is accurate and easy to calibrate but is not tractable. We evaluate our models against the commonly-used benchmark tractable model using a set of experiments that characterize the cycling behaviour of two Lithium-ion battery chemistries, as well as dynamic charge/discharge experiments. We further compare the models for two typical energy system applications, solar farm firming and grid regulation, to show the impact of the choice of battery model on the results. Finally, we evaluate the increase in accuracy when battery models are calibrated with the proper operating range.

(Invited) Strategies for Achieving High-Energy Density Storage Systems

Energy storage is vital for driving an energy independent world economy currently largely dependent on exploiting natural reserves supplemented by oil and gas exports. The field of Li-ion batteries has witnessed tremendous progress since the commercialization of the first Li-ion battery (LIB) by Sony in 1991. Correspondingly, there has been tremendous progress in the areas of cathode, electrolytes as well as anodes [1]. The area of lithiated transition metal oxides despite much advances, are still the flagship cathode systems largely focused on intercalation chemistry. However, the last two decades witnessed exploration of newer chemistries exploiting alloying and zintl phase formation focusing on silicon and tin as alternative anodes. Similarly, there has been tremendous research in the area of alternative energy storage systems beyond lithium-ion intercalation chemistry. Lithium-sulfur batteries (LSB) and Li metal anodes have accordingly emerged in the forefront and have been the spotlight of much research activity in recent years. All the systems are unfortunately, plagued by intransigent inferior electronic conductivity and voltage-specific phase transition related kinetic limitations accompanied with ensuing chemical, physical, and electrochemical challenges. Nano-engineered approaches coupled with the concomitant progress made in science and technology of synthetic and analytical materials chemistry appear primed for overcoming these hurdles. We have thus far, implemented dynamic theoretical and experimental strategies to develop engineered electronic and Li-ion conducting nanomaterials showing considerable promise as supporting components augmenting the performance and overcoming many of the limitations affecting these systems. Additionally, we have developed several approaches utilizing nanoscale droplets, nanoparticles, hollow Si nanotubes (h-SiNTs), cost-effective template derived nanoscale morphologies, scribable and flexible hetero-structured architectures displaying impressive capacities as high as ~3000 mAh/g with sustained cyclability and high rate capability in Si anodes[2]. Electrochemical approaches have also been developed for generating binder-less silicon based thin film anodes with considerable promise. Similarly, engineering approaches were implemented for generating sulfur cathodes in LSBs exploiting the tailored attributes of inorganic, nanocomposite, tethered, and polymeric lithium ion conducting (LIC) coupled with chemical framework materials (CFM) based matrices for encapsulating sulfur along with novel fine yarn-like and tethered architectures yielding 5.5 mAh/cm2 – 12 mAh/cm2 areal capacity as well as ~1200 mAh/g specific capacity with sulfur loadings as high as 20 mg/cm2 displaying up to 250 cycles cycling stability [3, 4]. New materials were identified serving as novel dendrite free anodes. Engineering strategies were also developed for stabilizing the Li metal anodes preventing and eliminating dendrite formation. These systems together have been studied as alternative safe anodes to the currently used Li metal anodes. Results of these studies will be presented and discussed. The presentation will also provide an insight into the promising future in store for generating tailored functional engineered systems in the rapidly evolving digitally savvy era of the 21st century as a pathway to potentially achieving energy independence in the near future. References Wang, P.N. Kumta, et al. ACS Nano (2011);Gattu, P.N. Kumta et al. Nano Research (2017)M. Shanthi, P.N. Kumta et al. Electrochimica Acta (2017)M. Shanthi, P.N. Kumta et al. Applied Energy Materials (2018)

Understanding the Electrochemical Deposition Process of Silver Metal

While lithium metal anode has been intensively studied in recent years, the unavoidable formation of solid electrolyte interphase (SEI) layers on Li surface implicates the fundamental understanding of the origin of uneven Li deposition driven by over potentials 1. Unlike Li, Ag has a very clean surface in contacting with the liquid electrolyte2 providing a good platform to study the mass transport process of metal cations in the solution phase and how they affect the final morphologies of Ag deposited. The effects of current density, and concentration of cation species on silver metal deposition firstly investigated and correlated to the various crystalline structures of Ag plated. Then different anions are added in the electrolyte to further understand how the coordination environments of Ag+ change in the presence of different anions and their impacts on the nucleation and growth process of Ag particles. A microelectrode was applied to measure the kinetic parameters such as diffusion coefficient and limited current density in different electrolytes. The kinetic and thermodynamic mechanisms governing the observed morphological changes in the deposited silver material will provide new insights for understanding the more complicated system such as Li deposition and inspire new solutions to fundamentally control the cation transport to realize the final morphology control of the electrochemically deposited metals. References Zhang, S. S. Problem, Status, and Possible Solutions for Lithium Metal Anode of Rechargeable Batteries. ACS Appl. Energy Mater. 1, 910–920 (2018).Suo, L. et al. “Water-in-salt” electrolyte enables high-voltage aqueous lithium-ion chemistries. Science 350, 938 (2015).

Eco-Efficiency of a Lithium-Ion Battery for Electric Vehicles: Influence of Manufacturing Country and Commodity Prices on GHG Emissions and Costs

Lithium-ion battery packs inside electric vehicles represents a high share of the final price. Nevertheless, with technology advances and the growth of the market, the price of the battery is getting more competitive. The greenhouse gas emissions and the battery cost have been studied previously, but coherent boundaries between environmental and economic assessments are needed to assess the eco-efficiency of batteries. In this research, a detailed study is presented, providing an environmental and economic assessment of the manufacturing of one specific lithium-ion battery chemistry. The relevance of parameters is pointed out, including the manufacturing place, the production volume, the commodity prices, and the energy density. The inventory is obtained by dismantling commercial cells. The correlation between the battery cost and the commodity price is much lower than the correlation between the battery cost and the production volume. The developed life cycle assessment concludes that the electricity mix that is used to power the battery factory is a key parameter for the impact of the battery manufacturing on climate change. To improve the battery manufacturing eco-efficiency, a high production capacity and an electricity mix with low carbon intensity are suggested. Optimizing the process by reducing the electricity consumption during the manufacturing is also suggested, and combined with higher pack energy density, the impact on climate change of the pack manufacturing is as low as 39.5 kg CO2 eq/kWh.

Biomimetic Solid-State Zn2+ Electrolyte for Corrugated Structural Batteries.

Batteries based on divalent metals, such as the Zn/Zn2+ pair, represent attractive alternatives to lithium-ion chemistry due to their high safety, reliability, earth-abundance, and energy density. However, archetypal Zn batteries are bulky, inflexible, non-rechargeable, and contain a corrosive electrolyte. Suppression of the anodic growth of Zn dendrites is essential for resolution of these problems and requires materials with nanoscale mechanics sufficient to withstand mechanical deformation from stiff Zn dendrites. Such materials must also support rapid transport Zn2+ ions necessary for high Coulombic efficiency and energy density, which makes the structural design of such materials a difficult fundamental problem. Here, we show that it is possible to engineer a solid Zn2+ electrolyte as a composite of branched aramid nanofibers (BANFs) and poly(ethylene oxide) by using the nanoscale organization of articular cartilage as a blueprint for its design. The high stiffness of the BANF network combined with the high ionic conductivity of soft poly(ethylene oxide) enable effective suppression of dendrites and fast Zn2+ transport. The cartilage-inspired composite displays the ionic conductance 10× higher than the original polymer. The batteries constructed using the nanocomposite electrolyte are rechargeable and have Coulombic efficiency of 96-100% after 50-100 charge-discharge cycles. Furthermore, the biomimetic solid-state electrolyte enables the batteries to withstand not only elastic deformation during bending but also plastic deformation. This capability make them resilient to different type of damage and enables shape modification of the assembled battery to improve the ability of the battery stack to carry a structural load. The corrugated batteries can be integrated into body elements of unmanned aerial vehicles as auxiliary charge-storage devices. This functionality was demonstrated by replacing the covers of several small drones with corrugated Zn/BANF/MnO2 cells, resulting in the extension of the total flight time. These findings open a pathway to the design and utilization of corrugated structural batteries in the future transportation industry and other fields of use.

A Wide Range of Testing Results on an Excellent Lithium-Ion Cell Chemistry to be used as Benchmarks for New Battery Technologies

We present a wide range of testing results on an excellent moderate-energy-density lithium-ion pouch cell chemistry to serve as benchmarks for academics and companies developing advanced lithium-ion and other “beyond lithium-ion” cell chemistries to (hopefully) exceed. These results are far superior to those that have been used by researchers modelling cell failure mechanisms and as such, these results are more representative of modern Li-ion cells and should be adopted by modellers. Up to three years of testing has been completed for some of the tests. Tests include long-term charge-discharge cycling at 20, 40 and 55°C, long-term storage at 20, 40 and 55°C, and high precision coulometry at 40°C. Several different electrolytes are considered in this LiNi0.5Mn0.3Co0.2O2/graphite chemistry, including those that can promote fast charging. The reasons for cell performance degradation and impedance growth are examined using several methods. We conclude that cells of this type should be able to power an electric vehicle for over 1.6 million kilometers (1 million miles) and last at least two decades in grid energy storage. The authors acknowledge that other cell format-dependent loss, if any, (e.g. cylindrical vs. pouch) may not be captured in these experiments.

Crystal Chemistry of Lithium Intermetallic Compounds: A Survey

The structural chemistry of lithium intermetallic compounds that are formed in Li–М binary systems where М = Ca, Sr, Ba, Mg, Zn, Cd, and Hg is surveyed. It is for the first time that the crystal structures of intermetallic compounds are classified in terms of polyhedral precursor metal clusters (in the program package ToposPro). The precursor metal clusters of crystal structures are identified using the algorithms of partitioning structural graphs into cluster structures and via the design of the basal 3D network of the structure in the form of a graph whose nodes correspond to the positions of the centers of precursor clusters. Tetrahedral precursor metal clusters M4 are identified for the crystal structures LiZn3-oC4, LiMg3-hP2, LiCd3-hP2, LiHg3-hP8, (LiMg3)(Li2Mg2)-tI16, Li2Zn2-cF16, Li2Cd2-cF16, Li2Hg2-cP2, Li3Cd-cF4, and Li3Hg-cF16; tetrahedral metal clusters M4 are found for the framework structures with spacer atoms Sr(Li2Sr2)-tP20, Ca2(Li4)-cF24, and Ca2(Li4)-cP12; tetrahedral metal clusters M4 and rings M6, for framework structures Ba3Li2(Li10)-hP30 and Ba3Li2(Li4In6)-hP30; icosahedral metal clusters M13 for the framework structure Li(Zn13)-cF112; bilayer tetrahedral metal clusters 0@М4@M22 for the framework structure Li23Sr6-cF116; and deltahedra М17 and deltahedra М30, for framework structures Sr4Li14 [Sr(Sr4Li12)] [(Sr2 (Sr8Li18)]-tI252 and Ba4Li14 [Ba(Ba4Li12)][(Ba2 (Ba8Li18)]-tI252. The scenario of crystal structure self-assembly from precursor metal clusters S30 in intermetallic compounds is reconstituted as: primary chain S31→ microlayer S32→ microframework S33.

Combo method prints batteries in any shape

Using three-dimensional printing, designers can make customized products, including shoe soles, engine parts, and hearing aids. But when designers want to make new personal electronics, their imaginations are limited by the shapes of existing batteries, such as coin shapes, rectangles, cylinders, and pouches. Harvard University materials scientist Jennifer Lewis, who specializes in materials and methods for 3-D printing, wants to make it possible for batteries to be designed around the electronics they will power, not vice versa. She and her colleagues have now combined 3-D printing and other techniques to make batteries in any shape, including rings, letters, circles, and more (ACS Nano 2018, DOI: 10.1021/acsnano.8b02744). In 2013, Lewis’s lab was the first to make 3-D-printed batteries using lithium-ion chemistry (Adv. Mater. 2013, DOI: 10.1002/adma.201301036). Because the materials in these batteries are water sensitive and flammable, she says, they had to do all their work in a glovebox filled with

Pseudoconcentrated Electrolyte with High Ionic Conductivity and Stability Enables High-Voltage Lithium-Ion Battery Chemistry

Electrolytes play a decisive role in determining the energy density, cycling life, safety, and temperature adaptability of lithium-ion batteries or any advanced battery chemistries. Here a “pseudoc...

Lithium ion supercapacitor composed by Si-based anode and hierarchal porous carbon cathode with super long cycle life

A lithium ion supercapacitor full cell is fabricated with a Fluorine-doped carbon encapsulated SiOx as anode and a Nitrogen-doped carbon with hierarchical meso-micro porous structure as cathode. Benefited from the fast kinetic lithium reaction as well as longevity in the newly synthesized Si-base anode and high capacitance on the porous carbon, the hybrid device delivering of high power density, high energy density and super long cycle life is demonstrated. After prelithiation of Si-base anode, this hybrid supercapacitor exhibits a high capacity of 120 mAh g−1 at 0.2 A g−1 after 1600 cycles. A capacity of 42 mAh g−1 can still be obtained even under the current density of 3 A g−1. Furthermore, Super long cycle life (45 mAh g−1 capacity with 1 A g−1 after 10,000 cycles), low leakage current (3.8 μA) and low self-discharge (82% voltage retention after 48 h resting in open-circuit potential) are revealed. This work presents not only a simple route for the synthesis of Si-base anode for energy storage devices on lithium chemistry, but also a new approach to the construction of hybrid battery-capacitor device.

SLMP® for Pre-Lithiation and Ultra-Thin Lithium Foil Anode Applications

Due to low first cycle coulombic efficiency, pre-lithiation techniques are accepted as a necessary enabling technology for high energy anodes such as Si/C composite materials. An independent source of active lithium can be combined electrochemically, chemically or physically with the anode to partially pre-lithiate and reduce first cycle inefficiency therefore increasing cathode utilization. (1) Electrochemical, ex-situ techniques, for example, roll-to-roll electrochemical baths and other techniques, including oversized cathode, lithium rich cathodes, sacrificial salts or in line short circuiting have been proposed. Among the physical techniques are vacuum deposition, sputtering, thermal spraying, and mechanical milling. (1) However, to-date, chemical pre-lithiation techniques have shown the most promise. Specifically, the ex-situ addition of metallic lithium to the anode material. The use of FMC’s advanced material, Lectro® Max Powder (SLMP) has been demonstrated worldwide as an effective and efficient pre-lithiation material. (1),(2),(3) SLMP can deliver capacity close to the theoretical lithium capacity of 3860 mAh/g and, after addition of the electrolyte, reacts with the anode material in-situ, and thus exists in the lithium ion form in the cell. (3) Because of its high capacity, addition of SLMP causes negligible increase in cell mass or volume unlike the case of sacrificial salts or oversized cathode use, which deliver lower capacity per unit mass and leave inactive phases after lithium extraction which might lower overall energy density of the cell. (1) In addition to use as a pre-lithiation agent to enable high energy anode materials SLMP could also be used to fully lithiate anode materials and thus allow the use of new cathode materials. (4) Most of beyond lithium ion chemistries and next generation lithium ion chemistries will require thin lithium metal anode use to achieve targeted volumetric energy density. Today, production of thin lithium foil involves extrusion of lithium metal followed by rolling to achieve desired thinness, which is complicated and expensive; thus, no commercially viable source of thin foil exists. SLMP-derived thin Li foil offers the possibility of achieving thin foil with width being limited only by the substrate used. In this work, we show the effectiveness of SLMP in improving the performance of commercially available silicon-based anode material. The anode composition is 85% SiO/C composite material and 15% Polyimide binder. The cathode composition is LiCoO2 (90%) + carbon black (5%) + PVdF (5%). Surface application technique was used to apply SLMP slurry onto the surface of prefabricated SiO electrodes. Single layer pouch SiO/LiCoO2 cells were assembled and 1M LiPF6 /EC+DEC (1:1) was used as the electrolyte. The pouch cells were conditioned at room temperature for 24 hours before the battery test. The pouch cell test protocol was: constant current charge at C/10 to 4.3 V, constant voltage charge at 4.3 V to C/100; constant current discharge at C/10 to 3.0 V. SLMP utilization has been evaluated based on its ability to compensate first cycle irreversible capacity. Figure 1 below shows the effect of SLMP on first cycle efficiency of SiO/LiCoO2 pouch cells. One of the important properties of SLMP is its specific capacity. SLMP contains at least 97% metallic lithium which can be fully utilized. To demonstrate this, an electrochemical system has been designed to test SLMP’s capacity, Li/Electrolyte/SLMP+Cu. About 1 mg of SLMP was deposited onto a half-inch Cu disc using a slurry of SLMP. After the solvent was fully evaporated, the electrode was calendered using 12,000 lbs pressure creating SLMP-derived thin Li foil. The electrodes were used to assemble coin cells with lithium foil counter electrode. 1M LiPF6/EC+DEC was used as the electrolyte. The cells were charged at 0.1 mA to 3.0 V. Figure 2 shows the voltage profiles for the cells comprised of SLMP-derived thin foil. The voltage profiles and the SLMP capacity are reproducible. Close to theoretical lithium capacity can be extracted from the SLMP derived thin foil. We will also discuss a novel SLMP delivery system which can be used at commercial scale to safely and economically incorporate SLMP into existing LIB systems as well as being used to produce ultra-thin lithium foil for solid state lithium applications. References Florian Holtstiege, Peer Bärmann, Roman Nölle, Martin Winter, and Tobias Placke, Pre-Lithiation Strategies for Rechargeable Energy Storage Technologies: Concepts, Promises and Challenges, Batteries 2018, 491), 4Margret Wohlfahrt-Mehrens, Manuel Weinberger, Novel strategies towards the realization of larger lithium sulfur/silicon pouch cells. Electrochimica Acta, Volume 191, 10, February (2016), p. 124–132.Y. Li, B. Fitch, Electrochem. Commun., 13, (2011) 664.K.B. Fitch, M.V. Yakovleva, Y. Li, I. Plitz, A. Skrzypczak, F. Badway, G.G. Amatucci, and Y. Gao, ECS Transaction 2007 Figure 1

Power capability prediction for lithium-ion batteries using economic nonlinear model predictive control

Technical challenges facing determination of battery available power arise from its complicated nonlinear dynamics, input and output constraints, and inaccessible internal states. Available solutions often resorted to open-loop prediction with simplified battery models or linear control algorithms. To resolve these challenges simultaneously, this paper formulates an economic nonlinear model predictive control to forecast a battery's state-of-power. This algorithm is built upon a high-fidelity model that captures nonlinear coupled electrical and thermal dynamics of a lithium-ion battery. Constraints imposed on current, voltage, temperature, and state-of-charge are then taken into account in a systematic fashion. Illustrative results from several different tests over a wide range of conditions demonstrate that the proposed approach is capable of accurately predicting the power capability with the error less than 0.2% while protecting the battery from undesirable reactions. Furthermore, the effects of temperature constraints, prediction horizon, and model accuracy are quantitatively examined. The proposed power prediction algorithm is general and then can be equally applicable to different lithium-ion batteries and cell chemistries where proper mathematical models exist.