Li-air Batteries Research Articles

Solid‐State Electrolytes for Lithium‐Air Batteries

Li‐air batteries (LABs) have attracted widespread attention due to their extremely high theoretical capacity and energy density. However, liquid LABs face safety issues such as flammability and leakage, which hinder their practical application. In comparison, solid‐state electrolytes (SSEs) possess excellent mechanical strength, good chemical stability, a wide electrochemical window, and non‐flammable characteristics, offering a feasible strategy for achieving stable and practical LABs. In this review, we will focus on the development and challenges of different kinds of SSEs, further their interfacial issues with electrodes, and finally propose strategies and outlooks for advanced solid‐state lithium‐air batteries (SSLABs). It is expected that this review will provide a systematic understanding and theoretical guidance for design of high‐performance SSLABs.

Theory-Guided Design of Unconventional Phase Metal Heteronanostructures for Higher-Rate Stable Li-CO2 and Li-Air Batteries.

Lithium-carbon dioxide (Li-CO2) and Li-air batteries hold great potential in achieving carbon neutral given their ultrahigh theoretical energy density and eco-friendly features. However, these Li-gas batteries still suffer from low discharging-charging rate and poor cycling life due to sluggish decomposition kinetics of discharge products especially Li2CO3. Here we report the theory-guided design and preparation of unconventional phase metal heteronanostructures as cathode catalysts for high-performance Li-CO2/air batteries. The assembled Li-CO2 cells with unconventional phase 4H/face-centered cubic (fcc) ruthenium-nickel heteronanostructures deliver a narrow discharge-charge gap of 0.65 V, excellent rate capability and long-term cycling stability over 200 cycles at 250 mA g-1. The constructed Li-air batteries can steadily run for above 150 cycles in ambient air. Electrochemical mechanism studies reveal that 4H/fcc Ru-Ni with high-electroactivity facets can boost redox reaction kinetics and tune discharge reactions towards Li2C2O4 path, alleviating electrolyte/catalyst failures induced by the aggressive singlet oxygen from solo decomposition of Li2CO3.

CO2- tolerant CuFe2O4 as Bifunctional Electrocatalyst for Transition from Rechargeable Li-O2 to Li-CO2 Batteries

CO2-tolerant rechargeable Lithium-Air batteries are seen as a high-performing alternative to Li-ion batteries. They utilize O2 from the air, reducing it at the cathode to form lithium peroxide (Li2O2) during discharge which is then oxidized to form lithium-metal and freeing O2 during charging. Most of the present studies involve pure O2 as the cathode material instead of aerial O2, which has a stiff-challenge due to atmospheric CO2 which produces Li2CO3 during discharge, posing a resistive load on the battery if not re-oxidized on charging. Ideally, presence of CO2 should enhance the charge-storage capacity if it is cycled reversibly. Thus, present research aims at taking advantage of both O2 and CO2 by employing metallic Cu on CuFe2O4 catalyst, synthesized from a one-step auto-combustion route. The Cu metal present in the catalyst leads to a low surface-area, yet the catalyst demonstrates excellent oxygen reduction reaction and moderate oxygen evolution reaction activity. excellent CO2 reduction reaction activity, oxidizing both the Li2O2 and the Li2CO3 during charge in both 10% CO2 and 100% CO2 atmospheres. The fabricated Li-CO2 battery operates for practical application, suggesting the suitability of the catalyst for the transition from practical Li-O2 battery to Li-Air battery.

Text Mining Analysis of Beyond Lithium-Ion Batteries

Li-ion batteries (LIBs) are the most commonly used energy storage technology in various consumer goods, including electric vehicles. However, several alternatives, so-called beyond-LIBs, are greatly investigated to decrease battery costs using abundant and globally distributed materials with high theoretical capacities. Among the diverse beyond LIB systems, this paper includes the top 6 researched chemistries: univalent (Na- and K-) and multivalent (Zn-) metal-ion, metal-air (Li-air and Zn-air), and Li-S batteries. Naturally, all these six battery chemistries have problems that must be addressed before mass commercialization. Although there are 24,523 publications on these batteries, a parallel examination of these technologies to transfer knowledge must be included in the literature. This study used text mining analysis to study the most common keywords and word connections for beyond-LIBs to learn from the general trends in the literature [1].First, the dataset was built using the Web of Science database in June 2023 by applying all the possible alternative names of beyond LIBs in the search with the Title option. Hence, the abstracts, author keywords, and keywords plus for each battery chemistry were obtained together with the article information. Afterward, data cleaning and text mining analysis were performed using the R Studio environment, specifically stringr, tm, pluralize, and tidytext libraries. The research interests in the primary battery parts and the single material-related words and two-word bigrams were investigated.The bibliometric analysis has shown that Li-S and Na-ion batteries are the most popular research areas in the beyond LIB literature. On the other hand, interestingly, Li-air batteries lost their popularity to Zn-air in around 2015. Publications on Zn-ion batteries have a sharp increasing trend, and K-ion batteries have started to share this research interest. When the single-word results are analyzed, it has been seen that anode, cathode, and electrolyte are the most commonly studied battery sections for Na- and K-ion, Zn-ion and Li-S, and finally, Zn- and Li-air batteries, respectively. Apart from the battery parts, regardless of the chemistry, the high frequency of carbon and graphene keywords are detected; hence, bigram analysis is further performed on these keywords to see the most associated words with these materials. It has been seen that carbon nanotubes are the first and nanofibers are the second preferred form of carbons, whereas the graphene oxides are found to be promising for all beyond LIBs, given only good results are reported in the literature.

Rate-Dependent Formation Processes in Li-O2 Batteries: Phase-Field Modeling with the Marcus Kinetics

Lithium-oxygen batteries (Li-O2) present a compelling prospect for the next generation of batteries owing to their exceptionally high theoretical energy density.[1] Yet, the performance of Li-O2 batteries is significantly limited by the current-dependent morphology of insulating oxides.[2-3] Existing mathematical models using Butler-Volmer kinetics exhibit uncertainties and inaccuracies.[4-5] In this study, we propose the integration of Marcus kinetics with the existing phase-field model to resolve a few outstanding inconsistencies between theoretical predictions and experimental discoveries. Notably, utilizing the Marcus kinetics enables a quantitative assessment of the role of solvation energy in current-dependet particle growth as opposed to film growth. Experimental results further verify the new theoretical predictions. This research offers valuable insights for the future design of Li-O2 batteries.[1] Bruce, P. G., Freunberger, S. A., Hardwick, L. J., & Tarascon, J.-M. (2012). Nucleation and growth of lithium peroxide in the Li-O2 battery. Nature Materials, 11, 19–29.[2] Read, J. (2002). Characterization of the Lithium/Oxygen Organic Electrolyte Battery. Journal of The Electrochemical Society, 149, A1190-A1195.[3] Kraytsberg, A., & Ein-Eli, Y. (2011). Review on Li–air batteries—Opportunities, limitations and perspective. Journal of Power Sources, 196, 886-893.[4] Lau, S., & Archer, L. A. (2015). Nucleation and growth of lithium peroxide in the Li-O2 battery. Nano Letters, 15(9), 6108–6114.[5] Horstmann, B., Gallant, B., Mitchell, R., Bessler, W. G., Shao-Horn, Y., & Bazant, M. Z. (2013). Rate-dependent morphology of Li2O2 growth in Li-O2 batteries. Journal of Physical Chemistry Letters, 4(24), 4227–4232.

A High Capacity Gas Diffusion Electrode for Li-O2 Batteries.

The very high theoretical specific energy of the lithium-air (Li-O2) battery (3500Wh kg-1) compared with other batteries makes it potentially attractive, especially for the electrification of flight. While progress has been made in realizing the Li-air battery, several challenges remain. One such challenge is achieving a high capacity to store charge at the positive electrode at practical current densities, without which Li-air batteries will not outperform lithium-ion. The capacity is limited by the mass transport of O2 throughout the porous carbon positive electrode. Here it is shown that by replacing the binder in the electrode by a polymer with the intrinsic ability to transport O2, it is possible to reach capacities as high as 31 mAh cm-2 at 1mA cm-2 in a 300µm thick electrode. This corresponds to a positive electrode energy density of 2650Wh L-1 and specific energy of 1716Wh kg-1, exceeding significantly Li-ion batteries and previously reported Li-O2 cells. Due to the enhanced oxygen diffusion imparted by the gas diffusion polymer, Li2O2 (the product of O2 reduction on discharge) fills a greater volume fraction of the electrode and is more homogeneously distributed.

From Li–O2 to Li–Air Batteries: Challenges and Progress on Oxygen-Permeable Membranes

From Li–O₂ to Li–Air Batteries: Challenges and Progress on Oxygen-Permeable Membranes

CoFe2O4 Nanoparticles on Bio-Based Polymer Derived Nitrogen Doped Carbon as Bifunctional Electrocatalyst for Li-Air Battery

Lithium-air batteries (LABs) are gaining attention as a promising energy storage solution. Their theoretical energy density of 3,505 Whkg−1 exceeds that of conventional lithium-ion batteries (500–800 Whkg−1). The commercial viability and widespread adoption of lithium-air batteries face challenges such as poor cycling stability, limited lifespan, and unresolved side reactions. In this study, we synthesized spinel CoFe2O4-decorated on bio-based poly(2,5-benzimidazole) derived N-doped carbon for electrocatalysts. Notably, strong metal-substrate interaction (SMSI) was observed through various characterizations. The bifunctional electrocatalytic activity and stability toward oxygen reduction reaction and oxygen evolution reaction were significantly enhanced by the SMSI, The LAB demonstrated a high discharge capacity of 18,356 mAhg−1 at a current density of 200 mAg−1, maintaining a remarkable discharge capacity of 1,000 mAhg−1 even at a high current density of 400 mAg−1 for 200 cycles. CoFe2O4-decorated on bio-derived ABPBI holds promise as a practical air-breathing electrode for high-capacity rechargeable LABs.

Recent Progress of Electrolyte Materials for Solid‐State Lithium–Oxygen (Air) Batteries

AbstractSolid‐state lithium–air batteries (SSLABs) have become the focus of next‐generation advanced batteries due to their safety and high energy densities. Current research on SSLABs is mainly centered on solid‐state electrolytes (SSEs). Although SSEs exhibit excellent properties, such as good stability, high safety, and great mechanical strength, they also display several distinct weaknesses of low ionic conductivities, poor stabilities in air, and high interfacial impedances, which will require sustained attentions for further investigations. This review first overviews the development history of SSEs achieved in terms of Li–air batteries. Subsequently, the fundamental properties, preparation methods, merits and drawbacks of different SSEs, along with their use in SSLABs, and the optimization strategy, especially for the inorganic solid electrolytes, polymer electrolytes, and hybrid electrolytes are comprehensively summarized. Finally, the research progresses made with SSEs are outlined, and critical insights and approaches for the remaining challenges of electrolytes and commercial application of SSLABs are proposed, which include advanced characterization, combining experiments and artificial intelligence such as theoretical calculations, and constructing selective permeability membranes. It is expected that this timely review will provide researchers with an integrated, systematic, and in‐depth understanding of SSEs and guidelines for future research, thus further promoting the commercial application of SSLABs.

Use of Perfluorochemicals in Li-Air Batteries: A Critical Review.

As lithium-ion (Li-ion) batteries approach their theoretical limits, alternative energy storage systems that can power technology with greater energy demands must be realized. Li-metal batteries, particularly Li-air batteries (LABs), are considered a promising energy storage candidate due to their inherent lightweight and energy-dense properties. Unfortunately, LAB practicality remains hindered by inadequate oxygen solubility and diffusion rates within the electrolyte, both which are fundamental for LAB operation. Due to exceptionally high oxygen solubilities, perfluorochemicals (PFCs) have been investigated as a promising solution to this issue. Although PFCs have been reported to enhance LAB performance and longevity when implemented within the cathodic regions of LABs in several studies, the influence of this class of compounds on other components of the battery (including the anode and the electrolyte) is also highly important. This paper reviews the use of PFCs in LABs to date and discusses the performance enhancements resulting from their implementation. We identify and discuss future prospects and emerging research directions for the use of PFCs into LAB design, in the effort toward realization of high-performing LAB technologies.

Engineering Triple-Phase Interfaces around the Anode toward Practical Alkali Metal-Air Batteries.

Alkali metal-air batteries (AMABs) promise ultrahigh gravimetric energy densities, while the inherent poor cycle stability hinders their practical application. To address this challenge, most previous efforts are devoted to advancing the air cathodes with high electrocatalytic activity. Recent studies have underlined the solid-liquid-gas triple-phase interface around the anode can play far more significant roles than previously acknowledged by the scientific community. Besides the bottlenecks of uncontrollable dendrite growth and gas evolution in conventional alkali metal batteries, the corrosive gases, intermediate oxygen species, and redox mediators in AMABs cause more severe anode corrosion and structural collapse, posing greater challenges to the stabilization of the anode triple-phase interface. This work aims to provide a timely perspective on the anode interface engineering for durable AMABs. Taking the Li-air battery as a typical example, this critical review shows the latest developed anode stabilization strategies, including formulating electrolytes to build protective interphases, fabricating advanced anodes to improve their anti-corrosion capability, and designing functional separator to shield the corrosive species. Finally, the remaining scientific and technical issues from the prospects of anode interface engineering are highlighted, particularly materials system engineering, for the practical use of AMABs.

Self-Catalyzed Growth of Co4N and N-Doped Carbon Nanotubes toward Bifunctional Cathode for Highly Safe and Flexible Li-Air Batteries.

The practical application of high-energy density lithium-oxygen (Li-O2) batteries is severely impeded by the notorious cycling stability and safety, which mainly comes from slow kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at cathodes, causing inferior redox overpotentials and reactive lithium metal in flammable liquid electrolyte. Herein, a bifunctional electrode, a safe gel polymer electrolyte (GPE), and a robust lithium anode are proposed to alleviate above problems. The bifunctional electrode is composed of N-doped carbon nanotubes (N-CNTs) and Co4N by in situ chemical vapor deposition self-catalyzed growth on carbon cloth (N-CNTs@Co4N@CC). The self-supporting, binder-free N-CNTs@Co4N@CC electrode has a strong and stable three-dimensional (3D) interconnected conductive structure, which provides interconnectivity between the active sites and the electrode to promote the transfer of electrons. Furthermore, the N-CNT-intertwined Co4N ensures efficient catalytic activity. Hence, the electrode demonstrates improved electrochemical properties even under a large current density (2000 mA g-1) and long cycling operation (250 cycles). Moreover, a highly safe and flexible rechargeable cell using the 3D N-CNTs@Co4N@CC electrode, GPE, and robust lithium anode design has been explored. The open circuit voltage is stable at ∼3.0 V even after 9800 cycles, which proves the mechanical durability of the integrated GPE cell. The stable cable-type Li-air battery was demonstrated to stably drive the light-emitting diodes (LEDs), highlighting the reliability for practical use.

Water-Capture Filter Paper Separator Realizing Ambient Li-Air Battery.

Lithium-air battery (LAB) is regarded as one of the most promising energy storage systems. However, the challenges arising from the lithium metal anode have significantly impeded the progress of LAB development. In this study, cellulose-based filter paper (FP) is utilized as a separator for ambient Li-air batteries to suppress dendrite growth and prevent H2O crossover. Thermogravimetric analysis and molecular spectrum reveal that FP enables ambient Li-air battery operation due to its surface functional groups derived from cellulose. The oxygen-enriched surface of cellulose not only enhances ion conductivity but also captures water and confines solvent molecules, thereby mitigating anode corrosion and side reactions. Compared with commercial glassfiber (GF) separator, this cellulose-based FP separator is cheaper, renewable, and environmentally friendly. Moreover, it requires less electrolyte while achieving prolonged and stable cycle life under real air environment conditions. This work presents a novel approach to realizing practical Li-air batteries by capturing water on the separator's surface. It also provides insights into the exploration and design of separators for enabling practical Li-air batteries toward their commercialization.

Organic Solvent-Based Li–Air Batteries with Cotton and Charcoal Cathode

We report on the construction and investigation of Li–air batteries consisting of a charcoal cathode and cotton texture soaked with different organic solvents containing a lithium triflate (LiOTf) electrolyte. Charcoal was found to be an appropriate cathode for Li–air batteries. Furthermore, cycling tests showed stable operation at over 800 cycles when dimethyl sulfoxide (DMSO) and diethylene glycol dimethyl ether (DEGME) were used as solvents, whereas low electrochemical stability was observed when propylene carbonate was used. The charging, discharging, and long-term discharging steps were mathematically modeled. Electrochemical impedance spectroscopy showed Gerischer impedance, suggesting intensive oxygen transport at the surface of the charcoal cathode. Diffusion, charge transfer, and solid electrolyte interphase processes were identified using distribution of relaxation time analysis. In the polypropylene (PP) membrane soaked with LiOTf in DEGME, three different states of Li ions were identified by 7Li-triple-quantum time proportional phase increment nuclear magnetic resonance measurements. On the basis of the latter results, a mechanism was suggested for Li-ion transport inside the PP membrane. The activity of the charcoal cathode was confirmed by Raman and cyclic voltammetry measurements.

Design of multifunctional interfaces on ceramic solid electrolytes for high-performance lithium-air batteries

High-energy-density lithium (Li)–air cells have been considered a promising energy-storage system, but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development. To address these above issues, solid-state Li–air batteries have been widely developed. However, many commonly-used solid electrolytes generally face huge interface impedance in Li–air cells and also show poor stability towards ambient air/Li electrodes. Herein, we fabricate a differentiating surface-regulated ceramic-based composite electrolyte (DSCCE) by constructing disparately LiI-containing polymethyl methacrylate (PMMA) coating and Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) layer on both sides of Li1.5Al0.5Ge1.5(PO4)3 (LAGP). The cathode-friendly LiI/PMMA layer displays excellent stability towards O2− and also greatly reduces the decomposition voltage of discharge products in Li–air system. Additionally, the anode-friendly PVDF-HFP coating shows low-resistance properties towards anodes. Moreover, Li dendrite/passivation derived from liquid electrolyte-induced side reactions and air/I-attacking can be obviously suppressed by the uniform and compact composite framework. As a result, the DSCCE-based Li–air batteries possess high capacity/low voltage polarization (11,836 mA h g−1/1.45 V under 500 mA g−1), good rate performance (capacity ratio under 1000 mA g−1/250 mA g−1 is 68.2%) and long-term stable cell operation (∼300 cycles at 750 mA g−1 with 750 mAh g−1) in ambient air.

An In Situ Gelled Polymer Electrolyte to Stabilize Lithium–Air Batteries

AbstractGel polymer‐based lithium batteries exhibit a unique combination of advantageous properties, including the favorable interfacial contact characteristic of liquid‐state batteries and the inherent stability of solid‐state batteries. For Li–air batteries operated in the semi‐open atmosphere, implementing in situ synthesized gel polymer electrolytes (GPEs) is effective in mitigating the environment‐induced challenges. In this study, a dimethyl sulfoxide (DMSO)‐based GPE in situ initiated by the toluene‐2,4‐diisocyanate (TDI) and 1,4‐benzenediboronic acid (BDBA) is designed to enable the stable operation of lithium–air batteries. The integration of in situ polymerization and polyvinyl alcohol's functional group engineering not only brings benefits to the interfacial contact and electrochemical stability of the battery but also mitigates the moisture sensitivity and volatility of the DMSO electrolyte in the ambient environment. In addition, the GPE can promote the formation of a robust protection film on the lithium surface. As a result, the designed GPE makes the batteries fully leverage their outstanding cycling stability in the ambient environment (241 cycles at 500 mA g−1 and 1000 mAh g−1). Moreover, an optimized Li–air pouch cell structure incorporating the GPE achieves a boasted energy density of 757.5 Wh kg−1, providing a significant technical pathway to bring Li–O2 batteries to practical Li–air batteries.

An integrally bilayered flexible cathode woven from CNTs for homogeneous hosting and fast electrocatalytic conversion of Li2O2 in Li-O2 battery

Due to the ultrahigh theoretical energy density, Li-O2 batteries are considered as potential candidates for power accessories for wearable electronic devices. An effective oxygen-breathing cathode is essential to enable high cyclic stability in Li-O2 batteries. Herein, an integrally bilayered, freestanding flexible Li-O2 battery cathode is constructed by in-situ growth of a layer of microflowers (which is an assembly of nitrogen-doped carbon nanotubes embedded with cobalt nanoparticles) on the surface of a CNT-interwoven film. Owing to the integrally bilayered structural feature and its compositional merits, such three-dimensionally conductive network provides a large space and surface area for homogeneous hosting and also enables efficient electrocatalytic conversion of the insulating Li2O2 solids. Thus obtained cathode delivers a large full capacity of 8.03 mAh cm−2; it also exhibits a low charge potential of approximately 3.6 V and excellent cyclic stability for stable operation up to nearly 2 months at a capacity of 0.1 and 1 mAh cm−2. Moreover, being flexible and binder-free, the cathode is highly robust, which can withstand repetitive folding and unfolding. A co-axial Li-air battery was fabricated accordingly, which exhibits excellent tolerance to bending deformation, showing great potential for application in flexible and wearable electronics.

LiOH Decomposition by NiO/ZrO2 in Li-Air Battery: Chemical Imaging with Operando Synchrotron Diffraction and Correlative Neutron/X-Ray Computed-Tomography Analysis.

Li-air batteries attract significant attention due to their highest theoretical energy density among all existing energy storage technologies. Currently, challenges related to extending lifetime and long-term stability limit their practical application. To overcome these issues and enhance the total capacity of Li-air batteries, this study introduces an innovative approach with NiO/ZrO2 catalysts. Operando advanced chemical imaging with micrometer spatial resolution unveils that NiO/ZrO2 catalysts substantially change the kinetics of crystalline lithium hydroxide (LiOH) formation and facilitate its rapid decomposition with heterogeneous distribution. Moreover, ex situ combined neutron and X-ray computed tomography (CT) analysis, provide evidence of distinct lithium phases homogeneously distributed in the presence of NiO/ZrO2. These findings underscore the material's superior physico-chemical and electronic properties, with more efficient oxygen diffusion and indications of lower obstruction to its active sites, avoiding clogging in the active electrode, a common cause of capacity loss. Electrochemical tests conducted at high current density demonstrated a significant kinetic enhancement of the oxygen reduction and evolution reactions, resulting in improved charge and discharge processes with low overpotential. This pioneering approach using NiO/ZrO2 catalysts represents a step toward on developing the full potential of Li-air batteries as high-energy-density energy storage systems.

A solid-state Li-air battery: computational studies of interfaces and relevance to discharge mechanism.

There is much interest in developing new energy storage systems to replace currently available ones that mainly work based on Li-ion intercalations. One attractive area is the Li-air battery for which most of the research has involved liquid electrolytes. There have been few studies on the use of a solid electrolyte in a Li-air battery. Recently, we reported the successful use of a solid-state electrolyte in a Li-air battery resulting in a Li2O product and potentially much higher energy density than in a Li-air battery based on either a Li2O2 or LiO2 product (Science, 2023, 379, 499). In this paper we discuss how the discharge mechanism involved in this solid-state Li-air battery differs from that of a Li-air battery with a liquid electrolyte. The solid-state mechanism is further explored with density functional studies of various interfaces involving the discharge product. We discuss the relevance of the results to the discharge mechanism in the solid-state Li-air battery.

Unlocking the efficiency of nonaqueous Li–air batteries through the synergistic effect of dual metal site catalysts: an interpretable machine learning approach

Screening transition metal combinations in dual metal site catalysts (DMSCs) for Li–air battery applications using supervised machine learning.