29 Search Results

Lithium–sulfur batteries (LSBs) are currently considered as promising candidates for next-generation energy storage technologies. However, their practical application is hindered by the critical issue of the polysulfide-shuttle. Herein, a metal organic framework (MOF)-derived solid electrolyte is presented to address it. The MOF solid electrolyte is developed based on a Universitetet i Oslo (UIO) structure. By grafting a lithium sulfonate (-SO₃Li) group to the UIO ligand, both the ionic conductivity and the polysulfide-suppression capability of the resulting -SO₃Li grafted UIO (UIOSLi) solid electrolyte are greatly improved. After integrating a Li-based ionic liquid (Li-IL), lithium bis(trifluoromethanesulfonyl)imide in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, the resulting Li-IL/UIOSLimore » solid electrolyte exhibits an ionic conductivity of 3.3 × 10^-4 S cm^-1 at room temperature. Based on its unique structure, the Li-IL/UIOSLi solid electrolyte effectively restrains the polysulfide shuttle and suppresses lithium dendritic growth. Lithium–sulfur cells with the Li-IL/UIOSLi solid electrolyte and a Li₂S₆ catholyte show stable cycling performance that preserves 84% of the initial capacity after 250 cycles with a capacity-fade rate of 0.06% per cycle.« less

Abstract This study presents a sodium‐ion conductive laminated polymer/ceramic‐polymer solid‐state electrolyte for the development of room‐temperature all‐solid‐state sodium batteries. At the negative electrode side, a negative‐electrode‐benign poly(ethylene oxide) (PEO) is used as a polymer matrix into which succinonitrile (SN) is integrated to improve the room‐temperature Na ⁺ ‐ion conductivity. At the positive electrode side, a cathode‐friendly poly(acrylonitrile) (PAN) serves as a polymer matrix into which a NASICON‐type ceramic solid‐electrolyte (Na ₃ Zr ₂ Si ₂ PO ₁₂ ) powder is incorporated toward both the enhancement of Na ⁺ ‐ion conductivity and the prevention of Na dendrite from penetrating through themore » electrolyte membrane. Through a strategical management of composition, the PAN‐Na ₃ Zr ₂ Si ₂ PO ₁₂ ‐NaClO ₄ composite and the PEO‐SN‐NaClO ₄ polymer deliver a balanced Na ⁺ ‐ion conductivity. Combining the two electrolyte layers, the laminated PEO‐SN‐NaClO ₄ /PAN‐Na ₃ Zr ₂ Si ₂ PO ₁₂ ‐NaClO ₄ solid electrolyte provides a Na ⁺ ‐ion conductivity of 1.36 × 10 ⁻⁴ S cm ⁻¹ at room temperature. With respect to the anodic friendly feature of the PEO‐SN‐NaClO ₄ layer and the cathodic friendly feature of the PAN‐Na ₃ Zr ₂ Si ₂ PO ₁₂ ‐NaClO ₄ layer, the laminated solid electrolyte presents a stable electrochemical window of 0–4.8 V. Room‐temperature all‐solid‐state sodium batteries fabricated with the laminated solid electrolyte, a Na‐metal negative electrode, and a Na ₂ MnFe(CN) ₆ positive electrode exhibit remarkably stable cyclability.« less

Lithium–sulfur (Li–S) batteries are being considered as one of the most promising candidates for the development of next-generation energy storage technologies. Although much progress has been made over the past decade, the development of Li–S batteries is still held back by a crucial polysulfide-shuttle problem. To address this critical issue, an approach to reduce the pore size of the separator is presented here, to prevent the penetration of soluble polysulfide species. A polymer with intrinsic nanoporosity (PIN) is developed within the micrometer-scale pores of a polypropylene separator. The framework of polypropylene acts as a skeleton to sustain reliable mechanical propertiesmore » with the thin membrane. Upon the formation of PIN in the pores, the polypropylene separator maintains its thickness. With the thin PIN–polypropylene membrane, the Li–S cells can be operated with a relatively high sulfur loading. The PIN allows the transport of Li⁺ ions, but suppresses the penetration of the polysulfide species. The Li–S batteries with the PIN-modified polypropylene separator exhibit enhanced cycling performance.« less

We report that the use of lithium-ion conductive solid electrolytes offers a promising approach to address the polysulfide-shuttle and the lithium-dendrite problems in lithium-sulfur (Li-S) batteries. One critical issue with the development of solid-electrolyte Li-S batteries is the electrode-electrolyte interfaces. We present herein a strategic approach by employing a thin layer of a polymer with intrinsic nanoporosity (PIN) on a Li⁺-ion conductive solid electrolyte, which significantly enhances the ionic interfaces between the electrodes and the solid electrolyte. Among the various types of Li⁺-ion solid electrolytes, NASICON-type Li_1+xAl_xTi_2-x(PO₄)₃ (LATP) offers advantages in terms of Li⁺-ion conductivity, stability in ambient environment, andmore » practical viability. However, LATP is susceptible to reaction with both the Li-metal anode and polysulfides in Li-S batteries due to the presence of easily reducible Ti⁴⁺ ions in it. The coating with a thin layer of PIN presented in this study overcomes the above issues. At the negative-electrode side, the PIN layer prevents the direct contact of Li-metal with the LATP solid electrolyte, circumventing the reduction of LATP by Li metal. Lastly, at the positive electrode side, the PIN layer prevents the migration of polysulfides to the surface of LATP, preventing the reduction of LATP by polysulfides.« less

Calcium represents a promising anode for the development of high-energy-density, low-cost batteries. Yet, a lack of suitable electrolytes has restricted the development of rechargeable batteries with a Ca anode. Furthermore, to achieve a high energy density system, sulfur would be an ideal cathode to couple with the Ca anode. Unfortunately, a reversible calcium-sulfur (Ca-S) battery has not yet been reported. Herein, a basic study of a reversible nonaqueous room-temperature Ca-S battery is presented. The reversibility of the Ca-S chemistry and high utilization of the sulfur cathode are enabled by employing a Li⁺-ion-mediated calcium-based electrolyte. Mechanistic insights pursued by spectroscopic, electrochemical,more » microscopic, and theoretical simulation (density functional theory) investigations imply that the Li⁺-ions in the Ca-electrolyte stimulate the reactivation of polysulfide/sulfide species. The coordination of lithium to sulfur reduces the formation of sturdy Ca-S ionic bonds, thus boosting the reversibility of the Ca-S chemistry. Furthermore, the presence of Li⁺-ions facilitates the ionic charge transfer both in the electrolyte and across the solid electrolyte interphase layer, consequently reducing the interfacial and bulk impedance of Ca-S batteries. As a result, both the utilization of active sulfur in the cathode and the discharge voltage of Ca-S batteries are significantly improved.« less

Redox flow batteries with organic electrode materials are attracting much attention. Previous research efforts have been focusing on liquid-phase electrodes on both the anode and cathode sides. Since batteries based on air cathodes can provide immense advantages, coupling a liquid organic electrode with a gaseous air cathode could offer multiple benefits in terms of cost, safety, and energy density. Herein we present a liquid–gaseous battery system with an aqueous methyl viologen (MV) anode and an air cathode. However, under the traditional battery operation principle with the same electrolyte at the anode and cathode, the resulting MV–air battery will not bemore » able to provide a reasonable voltage for practical applications. In this study, the cell voltage of the MV–air chemistry is strategically manipulated by using an acidic cathode electrolyte (catholyte) and a neutral anode electrolyte (anolyte). To operate a battery with different electrolytes at the anode and cathode, a sodium-ion (Na⁺-ion) conductive solid-state electrolyte (Na-SSE) membrane is employed to physically and electrically separate the two electrodes. In this work, the shuttling of sodium ions via the Na-SSE balances the ionic charge transfer between the two electrodes and sustains the redox reactions at the air cathode and the MV anode.« less

Earth-abundant element potassium (K) exhibiting a low reduction potential and a high gravimetric capacity is an ideal anode material for the development of low-cost and high-energy batteries. In this work, we present herein a mechanistic study of a reversible room-temperature nonaqueous potassium-sulfur (K-S) chemistry and demonstrate a rechargeable K-S cell. Electrochemical and spectroscopic studies reveal that the discharge-charge of the K-S couple involves transition processes of potassium polysulfide species, resembling that of the lithium-sulfur chemistry. Finally, through the design of a proper cathode-separator assembly, a deep discharge of the K-S cell with a high utilization of sulfur cathode is accessible.

We present that organic electrode materials such as quinones are drawing rising attention as promising redox-active materials for the development of rechargeable batteries. In aqueous solutions, the redox potential of quinones is dependent on the alkalinity and acidity of the medium. Under an alkaline condition, the oxidation potential of hydroquinone (existing as diphenolate) is ca. 0.8 V lower than that under an acidic condition. On the other hand, under an acidic condition, the reduction potential of oxygen is ca. 0.8 V higher than that under an alkaline condition. By taking these advantages, a Quinone-air cell with a rational voltage ismore » strategically demonstrated with an alkaline anode electrolyte and an acidic cathode electrolyte, which are physically separated by a Na⁺-ion conductive solid-state electrolyte membrane. Finally, the Na⁺-ions shuttling through the solid-state membrane act as ionic media-tors/messengers to sustain and link the redox reactions at the two electrodes.« less