Applications Of Metal Batteries Research Articles

Single Lithium-Ion Conducting Solid Polymer Electrolyte with Superior Electrochemical Stability and Interfacial Compatibility for Solid-State Lithium Metal Batteries.

Lithium metal batteries are being explored in meeting ever-increasing energy density needs. Because of serious dendritic lithium issues in liquid-state electrolytes, it is generally thought that solid-state electrolytes are potential alternatives for lithium metal batteries. Herein, we design a new single lithium-ion conducting lithium poly[(cyano)(4-styrenesulfonyl)imide] (LiPCSI) to replace the conventional dual-ion conducting salt for use in solid polymer electrolytes (SPEs) that successfully suppress the growth of lithium dendrites. Owing to highly delocalized anion moiety and oxidation-resistant cyano group, the tailored PEO8-LiPCSI SPE exhibits extremely high Li+ transference number (0.84) as well as oxidation potential (5.53 V vs Li+/Li). The symmetric Li/PEO8-LiPCSI/Li cell runs for 1000 h at 60 °C without a short circuit. The rechargeable solid-state Li/PEO8-LiPCSI/LiFePO4 cell discharges a capacity of 141 mAh g-1 with retention over 85% during 80 cycles. These merits enable the proposed PEO8-LiPCSI SPE to be very promising for solid-state lithium metal battery applications.

Enhanced ion transport in an ether aided super concentrated ionic liquid electrolyte for long-life practical lithium metal battery applications

We explore a superconcentrated electrolyte comprising N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide, 1,2 dimethoxyethane and 3.2 mol kg−1 LiFSI. It offers an alternative ion-transport mechanism, improved fluidity and ultra-stable Li metal battery performance.

An In Situ Polymerized Comb-Like PLA/PEG-based Solid Polymer Electrolyte for Lithium Metal Batteries

High ionic conductivity is a prerequisite for the application of solid-state polymer electrolyte towards the safe and high energy density electrochemical devices. Here we report the preparation and properties of an in-situ polymerized comb-like copolymer-based SPE (PLA/PEG-SPE) with high ionic conductivity from methyl acrylate functionalized poly(D,L-Lactide) (PLAMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA). A remarkably high ionic conductivity value of 6.9 × 10−5 S cm−1 at ambient temperature and a maximum ionic conductivity of 4.3 × 10−4 S cm−1 at 60°C were detected, with an activation energy of 0.2 eV and a Li+ transference number (tLi+) of 0.36. The PLA/PEG-SPE exhibits a wide electrochemical stability window up to 4.6 vs. Li/Li+ and very good lithium metal electrode compatibility. Solid-state LiFePO4/SPE/Li cells with integrated cathode and lithium metal deliver superior cycling stability with high discharge capacities (149 mAh g−1 as the initial specific capacity) and high capacity retention (exceeded 82% of its initial specific capacity) at 0.2 C at 60°C. The solid-state cells are also capable of being cycled at room temperature at 0.2 C. This work highlights a facile, in-situ fabrication strategy involving a vinyl-functionalized PLA precursor that yields a high-performance ion-conducting membrane attractive for lithium metal battery applications.

Enhanced electrochemical performance of lithium–sulphur battery by negating polysulphide shuttling and interfacial resistance through aluminium nanolayer deposition on a polypropylene separator

Shuttling of lithium polysulphides and the formation of lithium dendrites are the key challenges that impede the commercialization of high-capacity lithium–sulphur batteries. Here, we report on a binder-free novel aluminium nanolayer–coated polypropylene separator prepared by radio frequency magnetron sputtering technique for shuttle-free lithium metal battery applications. A symmetric cell with a modified separator exhibits smooth lithium striping and plating cycles at higher current density under room temperature conditions for an extended time period of 1550 h, suggesting better safety and protection of lithium anode from dendrite formation. Coin cells assembled with sulphurized cathode and Li metal as anode in a liquid electrolyte medium using a surface-modified separator display significantly improved specific initial discharge capacity with reasonable reversible discharge capacity and high Coulombic efficiency after 100 galvanostatic cycles at a cycling rate of 0.1 C. This result suggests that the aluminium nanolayer–coated separator can effectively help in reduction of polysulphide crossover during the electrochemical process.

Stable Li Metal Anode through Designed Solution Chemistry

Lithium metal is being extensively studied as an anode to replace graphite due to its high capacity and the lowest negative electrochemical potential. Current research focus is to mitigate lithium dendrite growth and to increase coulomb efficiency during electrochemical cycling by using various surface coatings, electrolyte additives.1, 2 In addition, a 3D host can be beneficial due to the reduced volume change.3 We have recently focused on designing novel electrolyte solution chemistry that enables dendrite free Li metal cycling. The structure, physical and chemical properties of the designed electrolyte solution are well in accordance with the quantum chemistry calculations. The XPS analysis of the SEI (solid electrolyte interface) components on the Li metal surface reveals that a LiF rich protection layer forms. As a result, a high average coulombic efficiency of 99.4% has been achieved at 0.5 mA cm-2 for 1 mAh cm-2 over 900 cycles. Even at a high current density of 10 mA cm-2, the coulombic efficiency of Li metal in this novel electrolyte is above 98.5%. A Li metal full cell with PANS (Poly(acrylonitrile) Sulfur) as cathode realizes a capacity retention of >98% over 900 cycles. This study offers a promising approach to enable highly stable Li metal battery applications. Acknowledgements This work was supported by the Office of Vehicle Technologies of the U.S. Department of Energy through the Advanced Battery Materials Research Program (Battery 500 Consortium) under Contract DE-EE0007764. Part of the work used the UCSD-MTI Battery Fabrication Facility and the UCSD-Arbin Battery Testing Facility. H. Liu, X. Wang, H. Zhou, H.-D. Lim, X. Xing, Q. Yan, Y. S. Meng and P. Liu, ACS Applied Energy Materials, 2018, DOI: 10.1021/acsaem.8b00348.H. Liu, H. Zhou, B.-S. Lee, X. Xing, M. Gonzalez and P. Liu, Acs Applied Materials & Interfaces, 2017, 9, 30635-30642.H. Liu, X. Yue, X. Xing, Q. Yan, J. Huang, V. Petrova, H. Zhou and P. Liu, Energy Storage Materials, 2018, DOI: https://doi.org/10.1016/j.ensm.2018.09.021.

Assessing structure and stability of polymer/lithium-metal interfaces from first-principles calculations

Solid polymer electrolytes (SPEs) are promising candidates for Li metal battery applications, but the interface between these two categories of materials has so far been studied only to a limited degree.

Stable cycling of high-voltage lithium metal batteries in ether electrolytes

The key to enabling long-term cycling stability of high-voltage lithium (Li) metal batteries is the development of functional electrolytes that are stable against both Li anodes and high-voltage (above 4 V versus Li/Li+) cathodes. Due to their limited oxidative stability ( 90% over 300 cycles and ~80% over 500 cycles with a charge cut-off voltage of 4.3 V. This study offers a promising approach to enable ether-based electrolytes for high-voltage Li metal battery applications. Ether-based electrolytes offer many advantages compared to other electrolyte systems, but they are not stable in Li metal batteries when operating at high voltages. Here, the authors develop a concentrated ether electrolyte that enables long-term cycling stability of high-voltage Li metal batteries.

All-solid-state lithium metal battery with solid polymer electrolytes based on polysiloxane crosslinked by modified natural gallic acid

Solid polymer electrolytes (SPEs) based on polysiloxane having ion-conducting poly(ethylene oxide) (PEO) groups crosslinked with modified gallic acid from natural resources are prepared by thiol-ene click reaction for all-solid-state lithium metal battery applications. The effects of composition and crosslinking density on physical and electrochemical properties of the SPEs are systematically studied. The SPEs are found to be thermally and mechanically stable even at elevated temperature due to stable crosslinked polymer networks by modified gallic acid crosslinker. Furthermore, ionic conductivity of SPE based on 80 mol% of PEO group and 20 mol% of modified gallic acid crosslinker is found to be comparable to that of polymer electrolyte having a wax state. The formation and growth of lithium dendrites are effectively suppressed by the SPE due to its good compatibility with lithium metal anode and mechanical suppression effect. All-solid-state lithium metal battery is fabricated with SPE-integrated cathode and it is found that SPE exhibits superior cycle performance to conventional liquid electrolyte/separator system at 60 °C that is attributed to the good thermal stability and lithium dendrite-suppressing ability of the SPE.

Stable Operation of Metal Anodes for Rechargeable Metal Battery Applications

Rechargeable metal batteries, such as Li metal batteries are considered the “holy grail” of energy storage systems. However, dendritic metal growth and limited Coulombic efficiency (CE) during metal deposition/stripping have prevented their practical applications in rechargeable batteries.1-3 During the last a few years, we have developed several approaches to suppress metal dendrite growth and enhance the Coulombic efficiency (CE) of metal deposition/stripping processes.2-7 Several electrolyte additives, including CsPF6, RbPF6, and trace-amount of H2O (25-50 ppm) have been found to be effective for achieving dendrite-free Li metal deposition in LiPF6-based electrolytes. Furthermore, we have developed a highly concentrated electrolytes composed of the lithium bis(fluorosulfonyl)imide (LiFSI) salt and 1,2-dimethoxyethane (DME) solvent which enables high rate cycling of Li metal anode at high CE (up to 99.1 %) without dendrite growth. It is demonstrated that a Li|Li cell can be cycled at high rates (10 mA cm-2) for more than 6,000 cycles with no increase in the cell impedance and no dendritic Li growth. A Li|Cu cell can be cycled at 4 mA cm-2 for more than 1,000 cycles with an average CE of 98.4%. We also demonstrate that the dendrite growth and CE of Li deposition is strongly depends on several other factors, such as substrate treatment, charge and discharge protocols, and cell pressure. By optimizing the electrolyte compositions and various operating parameters, CE of Li deposition/stripping has been further improved without dendrite growth. In addition to the high CE cycling of Li metal electrode, novel electrolyte was also developed which enables cycling of Na metal anode with an excellent CE (> 99.1%) as compared to a very low CE of less than 30% in conventional electrolytes. Further development of these approaches may lead to long term stable operation of Li and Na metal batteries. Acknowledgements This work was supported by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U. S. Department of Energy, Office of Science, Basic Energy Sciences (BES) and by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, the Advanced Battery Materials Research Programs of the U.S. Department of Energy (DOE). PNNL is operated by Battelle for the DOE under Contract DE-AC05-76RLO1830.

Surface reactions and performance of non-aqueous electrolytes with lithium metal anodes

Six electrolytes were investigated for lithium metal battery applications. The electrolytes were composed of combinations of four different salts (LiPF 6, LiB(C 2O 4) 2, LiI and LiN(SO 2CF 3) 2) and three different solvents (PC, DME, and 1,3-dioxolane). All six electrolytes had conductivities >3 mS cm −1 at temperatures from −20 to 40 °C. Electrochemical impedance spectroscopy (EIS) and linear polarization, both at room temperature and low temperature (−8 °C), provided congruent results. The LiI-based electrolyte had the lowest film resistance, while 0.7 M LiB(C 2O 4) 2–PC:DME (1:1) had the highest impedance. The presence of 1,3-dioxolane in electrolytes provided lower impedance with LiB(C 2O 4) 2 but higher resistance with LiPF 6-based electrolytes. NMR analysis of electrolytes after thermal abuse indicate that LiN(SO 2CF 3) 2-based electrolytes are the most thermally stable. SEM analysis suggests that surface modification and impedance changes are correlated.