Search

Manganese hexacyanoferrate is a promising cathode material for lithium and sodium ion batteries, however, it suffers of capacity fading during the cycling process. To access the structural and functional characteristics at the nanometer scale, fresh and cycled electrodes are extracted and investigated by transmission soft X‐ray microscopy, which allows chemical characterization with spatial resolution from position‐dependent x‐ray spectra at the Mn L‐, Fe L‐ and N K‐edges. Furthermore, soft X‐rays prove to show superior sensitivity toward Fe, compare to hard X‐rays. Inhomogeneities within the samples are identified, increasing in the aged electrodes, more dramatically in the Li‐ion system, which explains the poorer cycle life as Li‐ion cathode material. Local spectra, revealing different oxidation states over the sample with strong correlation between the Fe L‐edge, Mn L‐edge, and N K‐edge, imply a coupling between redox centers and an electron delocalization over the host framework. [ABSTRACT FROM AUTHOR]

High‐voltage nickel‐rich layered cathodes possess the requisite, such as excellent discharge capacity and high energy density, to realize lithium batteries with higher energy density. However, such materials suffer from structural and interfacial instability at high voltages (>4.3 V). To reinforce the stability of these cathode materials at elevated voltages, lithium borate salts are investigated as electrolyte additives to generate a superior cathode‐electrolyte interphase. Specifically, the use of lithium bis(oxalato)borate (LiBOB) leads to an enhanced cycling stability with a capacity retention of 81.7%. Importantly, almost no voltage hysteresis is detected after 200 cycles at 1C. This outstanding electrochemical performance is attributed to an enhanced structural and interfacial stability, which is attained by suppressing the generation of micro‐cracks and the superficial structural degradation upon cycling. The improved stability stems from the formation of a fortified borate‐containing interphase which protects the highly reactive cathode from parasitic reactions with the electrolyte. Finally, the decomposition process of LiBOB and the possible adsorption routes to the cathode surface are deduced and elucidated. [ABSTRACT FROM AUTHOR]

Manganese hexacyanoferrates (MnHCF) are promising positive electrode materials for non‐aqueous batteries, including Na‐ion batteries, due to their large specific capacity (>130 mAh g−1), high discharge potential and sustainability. Typically, the electrochemical reaction of MnHCF associates with phase and structural changes, due to the Jahn‐Teller (JT) distortion of Mn sites upon the charge process. To understand the effect of the MnHCF structure on its electrochemical performance, two MnHCF materials with different vacancies content are investigated herein. The electrochemical results show that the sample with lower vacancy content (4 %) exhibits relatively higher capacity retention of 99.1 % and 92.6 % at 2nd and 10th cycles, respectively, with respect to 97.4 % and 79.3 % in sample with higher vacancy content (11 %). Ex‐situ X‐ray absorption spectroscopy (XAS) and ex situ X‐ray diffraction (XRD) characterization results show that a weaker cooperative JT‐distortion effect and relatively smaller crystal structure modification occurred for the material with lower vacancies, which explains the better electrochemical performance in cycled electrodes. [ABSTRACT FROM AUTHOR]

Solid‐state batteries (SSBs) with high‐voltage cathode active materials (CAMs) such as LiNi1−x−yCoxMnyO2 (NCM) and poly(ethylene oxide) (PEO) suffer from "noisy voltage" related cell failure. Moreover, reports on their long‐term cycling performance with high‐voltage CAMs are not consistent. In this work, we verified that the penetration of lithium dendrites through the solid polymer electrolyte (SPE) indeed causes such "noisy voltage cell failure". This problem can be overcome by a simple modification of the SPE using higher molecular weight PEO, resulting in an improved cycling stability compared to lower molecular weight PEO. Furthermore, X‐ray photoelectron spectroscopy analysis confirms the formation of oxidative degradation products after cycling with NCM, for what Fourier transform infrared spectroscopy is not suitable as an analytical technique due to its limited surface sensitivity. Overall, our results help to critically evaluate and improve the stability of PEO‐based SSBs. [ABSTRACT FROM AUTHOR]

The poorly flammable room‐temperature ionic liquid‐based electrolyte composed of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and N‐butyl‐N‐methylpyrrolidinium bis(fluorosulfonyl)imide (Pyr14FSI) with fluoroethylene carbonate (FEC) as an additive is investigated towards its compatibility with the LiNi0.88Co0.09Mn0.03O2 (NCM88) cathode and a high‐capacity Si/graphite (SiG) anode, revealing a remarkably stable performance in lithium‐ion cells. Interestingly, this dual‐anion electrolyte with FEC additive forms a stable electrode‐electrolyte interphase on both sides, which suppresses the morphological degradation of the electrode materials and continuous electrolyte decomposition. Consequently, lithium‐ion cells using such dual‐anion ionic liquid‐based electrolyte display significantly improved cycling stability compared to conventional carbonate ester‐based electrolyte, achieving a high specific energy of 385 Wh kg−1 (based on both cathode and anode active materials weight) with a capacity retention of 74 % after 200 cycles at 0.2 C, demonstrating the possibility to realize safe and high energy density LIBs. [ABSTRACT FROM AUTHOR]

Lithium metal batteries (LMBs) with nickel‐rich cathodes are promising candidates for next‐generation, high‐energy batteries. However, the highly reactive electrodes usually exhibit poor interfacial compatibility with conventional electrolytes, leading to limited cyclability. Herein, a locally concentrated ionic liquid electrolyte (LCILE) consisting of lithium bis(fluorosulfonyl)imide (LiFSI), 1‐ethyl‐3‐methylimidazolium bis(fluorosulfonyl)imide (EmimFSI), and 1,2‐difluorobenzene (dFBn) is designed to overcome this challenge. As a cosolvent, dFBn not only promotes the Li+ transport with respect to the electrolyte based on the ionic liquid only, but also has beneficial effects on the electrode/electrolyte interphases (EEIs) on lithium metal anodes (LMAs) and LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes. As a result, the developed LCILE enables dendrite‐free cycling of LMAs with a coulombic efficiency (CE) up to 99.57% at 0.5 mA cm−2 and highly stable cycling of Li/NMC811 cells (4.4 V) at C/3 charge and 1 C discharge (1 C = 2 mA cm−2) for 500 cycles with a capacity retention of 93%. In contrast, the dFBn‐free electrolyte achieves lithium stripping/plating CE, and the Li/NMC811 cells' capacity retention of only 98.22% and 16%, respectively under the same conditions. The insight into the coordination structure, promoted Li+ transport, and EEI characteristics gives fundamental information essential for further developing (IL‐based) electrolytes for long‐life, high‐energy LMBs. [ABSTRACT FROM AUTHOR]

The full commercialization of sodium‐ion batteries (SIBs) is still hindered by their lower electrochemical performance and higher cost ($ W−1 h−1) with respect to lithium‐ion batteries. Understanding the electrode–electrolyte interphase formation in both electrodes (anode and cathode) is crucial to increase the cell performance and, ultimately, reduce the cost. Herein, a step forward regarding the study of the cathode–electrolyte interphase (CEI) by means of X‐ray photoelectron spectroscopy (XPS) has been carried out by correlating the formation of the CEI on the P2‐Na0.67Mn0.8Ti0.2O2 layered oxide cathode with the cycling rate. The results reveal that the applied current density affects the concentration of the formed interphase species, as well as the thickness of CEI, but not its chemistry, indicating that the electrode–electrolyte interfacial reactivity is mainly driven by thermodynamic factors. [ABSTRACT FROM AUTHOR]

Aqueous ammonium‐ion (NH4+) batteries (AAIB) are a recently emerging technology that utilize the abundant electrode resources and the fast diffusion kinetics of NH4+ to deliver an excellent rate performance at a low cost. Although significant progress has been made on AAIBs, the technology is still limited by various challenges. In this Minireview, the most recent advances are comprehensively summarized and discussed, including cathode and anode materials as well as the electrolytes. Finally, a perspective on possible solutions for the current limitations of AAIBs is provided. [ABSTRACT FROM AUTHOR]

High‐energy Ni‐rich lithium transition metal oxides such as Li[Ni0.8Co0.1Mn0.1]O2 (NCM811) are appealing positive electrode materials for next‐generation lithium batteries. However, the high sensitivity toward moist air during storage and the high reactivity with common organic electrolytes, especially at elevated temperatures, are hindering their commercial use. Herein, an effective strategy is reported to overcome these issues by coating the NCM811 particles with a lithium phosphonate functionalized poly(aryl ether sulfone). The application of this coating allows for a substantial reduction of lithium‐based surface impurities (e.g., LiOH, Li2CO3) and, generally, the suppression of detrimental side reactions upon both storage and cycling. As a result, the coated NCM811‐based cathodes reveal superior Coulombic efficiency and cycling stability at ambient and, particularly, at elevated temperatures up to 60 °C (a temperature at which the non‐coated NCM811 electrodes rapidly fail) owing to the formation of a stable cathode electrolyte interphase with enhanced Li+ transport kinetics and the well‐retained layered crystal structure. These results render the herein presented coating strategy generally applicable for high‐performance lithium battery cathodes. [ABSTRACT FROM AUTHOR]

In the family of Zn/manganese oxide batteries with mild aqueous electrolytes, cubic α‐Mn2O3 with bixbyite structure is rarely considered, because of the lack of the tunnel and/or layered structure that are usually believed to be indispensable for the incorporation of Zn ions. In this work, the charge storage mechanism of α‐Mn2O3 is systematically and comprehensively investigated. It is demonstrated that the electrochemically induced irreversible phase transition from α‐Mn2O3 to layered‐typed L‐ZnxMnO2, coupled with the dissolution of Mn2+ and OH− into the electrolyte, allows for the subsequent reversible de‐/intercalation of Zn2+. Moreover, it is proven that α‐Mn2O3 is not a host for H+. Instead, the MnO2 formed from L‐ZnxMnO2 and the Mn2+ in the electrolyte upon the initial charge is the host for H+. Based on this electrode mechanism, combined with fabricating hierarchically structured mesoporous α‐Mn2O3 microrod array material, an unprecedented rate capability with 103 mAh g−1 at 5.0 A g−1 as well as an appealing stability of 2000 cycles (at 2.0 A g−1) with a capacity decay of only ≈0.009% per‐cycle are obtained. [ABSTRACT FROM AUTHOR]

Rechargeable Li-based battery technologies utilising silicon, silicon-based, and Si-derivative anodes coupled with high-capacity/high-voltage insertion-type cathodes have reaped significant interest from both academic and industrial sectors. This stems from their practically achievable energy density, offering a new avenue towards the mass-market adoption of electric vehicles and renewable energy sources. Nevertheless, such high-energy systems are limited by their complex chemistry and intrinsic drawbacks. From this perspective, we present the progress, current status, prevailing challenges and mitigating strategies of Li-based battery systems comprising silicon-containing anodes and insertion-type cathodes. This is accompanied by an assessment of their potential to meet the targets for evolving volume- and weight-sensitive applications such as electro-mobility. Large-scale manufacturing of high-energy Li-ion cells is of paramount importance for developing efficient rechargeable battery systems. Here, the authors report in-depth discussions and evaluations on the use of silicon-containing anodes together with insertion-based cathodes. [ABSTRACT FROM AUTHOR]

Featured Application: We present analysis strategies for soft X-ray transmission imaging data focused on the study of chemical and morphological properties of cathode material for lithium batteries. Energy-dependent full field transmission soft X-ray microscopy (TXM) is able to give a full picture at the nanometer scale of the chemical state and spatial distribution of oxygen and other elements relevant for battery materials, providing pixel-by-pixel absorption spectrum. We show different methods to localize chemical inhomogeneities in Li1.2Mn0.56Ni0.16Co0.08O2 particles with and without VOx coating extracted from electrodes at different states of charge. Considering the 3d(Mn,Ni)-2p(O) hybridization, it has been possible to discriminate the chemical state of Mn and Ni in addition to the one of O. Different oxidation states correspond to specific features in the O-K spectra. To localize sample regions with specific compositions we apply two different methods. In the first, the pixel-by-pixel ratios of images collected at different key energies clearly highlight local inhomogeneities. In the second, introduced here for the first time, we directly correlate corresponding pixels of the two images on a xy scatter plot that we call phase map, where we can visualize the distributions as function of thickness as well as absorption artifacts. We can select groups of pixels, and then map regions with similar spectral features. Core-shell distributions of composition are clearly shown in these samples. The coating appears in part to frustrate some of the usual chemical evolution. In addition, we could directly observe several further aspects, such as: distribution of conducting carbon; inhomogeneous state of charge within the electrode; molecular oxygen profiles within a particle. The latter suggests a surface loss with respect to the bulk but an accumulation layer at intermediate depth that could be assigned to retained O2. [ABSTRACT FROM AUTHOR]

Abstract: Herein, the successful synthesis of MnPO4‐coated LiNi0.4Co0.2Mn0.4O2 (MP‐NCM) as a lithium battery cathode material is reported. The MnPO4 coating acts as an ideal protective layer, physically preventing the contact between the NCM active material and the electrolyte and, thus, stabilizing the electrode/electrolyte interface and preventing detrimental side reactions. Additionally, the coating enhances the lithium de‐/intercalation kinetics in terms of the apparent lithium‐ion diffusion coefficient. As a result, MP‐NCM‐based electrodes reveal greatly enhanced C‐rate capability and cycling stability—even under exertive conditions like extended operational potential windows, elevated temperature, and higher active material mass loadings. This superior electrochemical behavior of MP‐NCM compared to as‐synthesized NCM is attributed to the superior stability of the electrode/electrolyte interface and structural integrity when applying a MnPO4 coating. Employing an ionic liquid as an alternative, intrinsically safer electrolyte system allows for outstanding cycling stabilities in a lithium‐metal battery configuration with a capacity retention of well above 85% after 2000 cycles. Similarly, the implementation in a lithium‐ion cell including a graphite anode provides stable cycling for more than 2000 cycles and an energy and power density of, respectively, 376 Wh kg−1 and 1841 W kg−1 on the active material level. [ABSTRACT FROM AUTHOR]

Abstract: Sodium‐ion technology has the potential to become the next generation of low cost and environmentally friendly electrochemical energy storage system for grid‐level applications. The low cost and abundant raw materials employed in sodium cells have driven the recent increasing interest in sodium‐ion batteries (SIBs), which appear especially appealing, since manufacturers can use the already existing production technology of lithium‐ion batteries. However, SIBs are still an early stage technology, which requires several issues affecting cell performance to be addressed. Despite the accelerated development of cathode materials, anode materials still require further investigation and optimization to reach high energy density performance. In the pursuit of high capacity anode materials, several alloying‐, conversion‐, and combined conversion–alloying‐based electrodes have been investigated. This review offers a comprehensive overview on the recent progresses toward the realization of “beyond‐insertion” anode materials. The role of nanostructuration with the associated advantages and disadvantages is presented for each class of compounds, combined with the main strategies adopted to improve the electrochemical behavior. Finally, an overview of the challenges and perspectives associated with the development of the next generation of anode materials is presented with a particular focus on the role of the electrolyte solutions and solid/electrolyte interphase. [ABSTRACT FROM AUTHOR]

Abstract: Aqueous Na‐ion batteries may offer a solution to the cost and safety issues of high‐energy batteries. However, substantial challenges remain in the development of electrode materials and electrolytes enabling high performance and long cycle life. Herein, we report the characterization of a symmetric Na‐ion battery with a NASICON‐type Na2VTi(PO4)3 electrode material in conventional aqueous and “water‐in‐salt” electrolytes. Extremely stable cycling performance for 1000 cycles at a high rate (20 C) is found with the highly concentrated aqueous electrolytes owing to the formation of a resistive but protective interphase between the electrode and electrolyte. These results provide important insight for the development of aqueous Na‐ion batteries with stable long‐term cycling performance for large‐scale energy storage. [ABSTRACT FROM AUTHOR]

This work reports the synthesis and characterization of an amorphous V2O5 cryogel/graphene nanosheet composite as a high-performance cathode material. The optimization of electrode processing is conducted by using the environmentally friendly poly acrylic acid as the binder and ethanol as the solvent. The nanocomposite material shows outstanding capacity values, exceeding 300 mAhg−1 reversible capacity upon galvanostatic cycling tests at 280 mAg−1 (C/2 charge/discharge rate), and more than 100 mAhg−1 at 5600 mAg−1 (10C). A subsequent electrochemical impedance spectroscopy study gives useful insights into the cathode/electrolyte interface. [ABSTRACT FROM AUTHOR]

Vanadium oxide is an attractive high-capacity cathode material for metal batteries, but it is affected by severe capacity fading upon cycling in conventional electrolytes. In this manuscript, it is shown that the cycling ability of vanadium oxide (V2O5) aerogel cathodes can be substantially improved by using properly designed electrolytes. In particular, the electrochemical characterization of V2O5 aerogel, in combination with room-temperature ionic liquid-based electrolytes, demonstrates cycling stabilities above 600 cycles with capacity retentions higher than 80 %. Furthermore, the ionic liquid-based electrolytes grant cyclability and safety in lithium-metal batteries even above room temperature. [ABSTRACT FROM AUTHOR]

Herein, the synthesis of new quaternary layered Na-based oxides of the type Na xMn yNi zFe0.1Mg0.1O2 (0.67≤ x ≤ 1.0; 0.5≤ y ≤ 0.7; 0.1≤ z ≤ 0.3) is described. The synthesis can be tuned to obtain P2- and O3-type as well as mixed P-/O-type phases as demonstrated by structural, morphological, and electrochemical properties characterization. Although all materials show good electrochemical performance, the simultaneous presence of the P- and O-type phases is found to have a synergetic effect resulting in outstanding performance of the mixed phase material as a sodium-ion cathode. The mixed P3/P2/O3-type material, having an average elemental composition of Na0.76Mn0.5Ni0.3Fe0.1Mg0.1O2, overcomes the specific drawbacks associated with the P2- and O3-type materials, allowing the outstanding electrochemical performance. In detail, the mixed phase material is able to deliver specific discharge capacities of up to 155 mAh g−1 (18 mA g−1) in the potential range of 2.0-4.3 V. In the narrower potential range of 2.5-4.3 V the material exhibits high average discharge potential (3.4 V versus Na/Na+), exceptional average coulombic efficiencies (>99.9%), and extraordinary capacity retention (90.2% after 601 cycles). The unexplored class of P-/O-type mixed phases introduces new perspectives for the development of layered positive electrode materials and powerful Na-ion batteries. [ABSTRACT FROM AUTHOR]

As existing battery technologies struggle to meet the requirements for widespread use in the field of large-scale energy storage, novel concepts are urgently needed concerning batteries that have high energy densities, low costs, and high levels of safety. Here, a novel eco-friendly energy storage system (ESS) using seawater and an ionic liquid is proposed for the first time; this represents an intermediate system between a battery and a fuel cell, and is accordingly referred to as a hybrid rechargeable cell. Compared to conventional organic electrolytes, the ionic liquid electrolyte significantly enhances the cycle performance of the seawater hybrid rechargeable system, acting as a very stable interface layer between the Sn-C (Na storage) anode and the NASICON (Na3Zr2Si2PO12) ceramic solid electrolyte, making this system extremely promising for cost-efficient and environmentally friendly large-scale energy storage. [ABSTRACT FROM AUTHOR]

The synthesis of a new layered cathode material, Na0.5[Ni0.23Fe0.13Mn0.63]O2, and its characterization in terms of crystalline structure and electrochemical performance in a sodium cell is reported. X-ray diffraction studies and high resolution scanning electron microscopy images reveal a well-defined P2-type layered structure, while the electrochemical tests demonstrate excellent characteristics in terms of high capacity and cycle life. This performance, the low cost, and the environmental compatibility of its component poses Na0.5[Ni0.23Fe0.13Mn0.63]O2 to be among the most promising materials for the next generation of sodium-ion batteries. [ABSTRACT FROM AUTHOR]

The article offers information related to the development of lithium-ion batteries (LIBs) focusing on the challenges in its development. It mentions several types LIBs that were developed using various materials including LIB electrodes created through anodes, LIB electrodes developed using cathodes, and LIB electrolytes created using organic carbonate mixed solvents such as ethylene carbonate-dimethyl carbonate (EC:DMC).

We investigated an N-heterocyclic-carbene-PF5 adduct (NHC-PF5) as additive for overcharge protection of a lithium nickel cobalt oxide (NCM) cathode by linear potential sweep methods and constant current experiments. The NHC-PF5 additive was oxidized at a potential of 4.57 V vs. Li/Li+ thus protecting the NCM cathode from overcharge. No detrimental influence of the additive on the cycling behavior of NCM/graphite full cells was observed. [ABSTRACT FROM AUTHOR]

We report here the characterization of Li battery electrolytes based upon the N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ionic liquid (PY14FSI) with lithium bis(fluorosulfonyl)imide (LiFSI) as a support salt. These electrolytes show low viscosity relative to other pyrrolidinium-based ionic liquids (ILs) and corresponding higher conductivity at subambient temperatures. The melting point of the IL decreases with the addition of LiFSI and concentrated samples remain totally amorphous. The electrolytes exhibit decreased thermal stability and increased parasitic cathodic reactions with increasing LiFSI fraction relative to the pure IL. probably due to a higher impurity level for the commercial LiFSI. Despite this, the electrolytes have excellent lithium cycling behavior at 20°C. [ABSTRACT FROM AUTHOR]

Keywords: cathode/electrolyte interface; electrolyte additive; lithium-ion battery; NMC; X-ray photoelectron spectroscopy A comprehensive XPS study on the cathode/electrolyte interface layer formed on LiNi SB 0.5 sb Mn SB 0.3 sb Co SB 0.2 sb O SB 2 sb electrodes cycled up to 4.5 V, elucidates the chemical composition, thickness and morphology evolution with different electrolytes allowing a correlation between the interface layer nature and the electrochemical performance. Cathode/electrolyte interface, electrolyte additive, lithium-ion battery, NMC, X-ray photoelectron spectroscopy. [Extracted from the article]

Herein, the synthesis of a novel lithium sulfide (Li2S)‐based material is presented. The material is composed of Li2S and lithium sulfenamide, which are formed in and coprecipitated from an ethylenediamine solution as an amorphous, but solid compound. The sulfenamide compound is shown to be an effective carbon source to obtain carbon‐coated Li2S via post‐processing. Both the pristine and carbon‐coated materials are characterized by a series of physicochemical methods and preliminarily investigated for application in batteries. The pristine material possesses a remarkably low activation potential. This ease of activation is particularly beneficial for solid‐state cells, where the material shows a much better performance than the commercially available Li2S. [ABSTRACT FROM AUTHOR]

Lithium-Ion Batteries: Elucidating the Effect of Iron Doping on the Electrochemical Performance of Cobalt-Free Lithium-Rich Layered Cathode Materials (Adv. The introduction of iron reduces nickel migration into the transition metal layer and helps to suppress the accompanying structural transformation, the root cause of the voltage fading of LRNM-layered cathodes. Cobalt free, iron doping, lithium-ion batteries, lithium-rich materials, voltage fading. [Extracted from the article]

The eco‐friendly and low‐cost Co‐free Li1.2Mn0.585Ni0.185Fe0.03O2 is investigated as a positive material for Li‐ion batteries. The electrochemical performance of the 3 at% Fe‐doped material exhibits an optimal performance with a capacity and voltage retention of 70 and 95%, respectively, after 200 cycles at 1C. The effect of iron doping on the electrochemical properties of lithium‐rich layered materials is investigated by means of in situ X‐ray diffraction spectroscopy and galvanostatic intermittent titration technique during the first charge–discharge cycle while high‐resolution transmission electron microscopy is used to follow the structural and chemical change of the electrode material upon long‐term cycling. By means of these characterizations it is concluded that iron doping is a suitable approach for replacing cobalt while mitigating the voltage and capacity degradation of lithium‐rich layered materials. Finally, complete lithium‐ion cells employing Li1.2Mn0.585Ni0.185Fe0.03O2 and graphite show a specific energy of 361 Wh kg−1 at 0.1C rate and very stable performance upon cycling, retaining more than 80% of their initial capacity after 200 cycles at 1C rate. These results highlight the bright prospects of this material to meet the high energy density requirements for electric vehicles. [ABSTRACT FROM AUTHOR]

In article number 1501555, Daniel Buchholz, Stefano Passerini and co‐workers present a novel cathode material for sodium‐ion batteries, consisting of mixed layered transition metal oxides. The material, prepared through a solid‐state synthesis under equilibrium conditions to obtain all phases in their most stable composition, revealed outstanding electrochemical long‐term performance. This, rather unexplored, class of mixed materials overcomes the drawbacks associated with pure phases. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries are regarded as a complementary drop-in technology to lithium-ion batteries because they promise lower cost and a higher degree of environmental friendliness. Among other reasons, these benefits come from the use of manganese-based materials, whose stabilization via cation substitution is intensively studied to improve the electrochemical performance. Although multiple elements have been considered as substituent, surprisingly, boron has not been reported for layered sodium-ion cathode materials up to date. Our investigation of layered Na 2/3 B 0.11 Mn 0.89 O 2 reveals an unexpectedly good electrochemical performance, with charge and discharge capacities of more than 175 mAh g −1 at 10 mA g −1 and 135 mAh g −1 at 500 mA g −1 . The measured capacities are among the highest ever reported for sodium-based layered oxides in the potential range of 4.0–2.0 V vs. Na/Na + . [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous rechargeable batteries offer a safe alternative for electrochemical energy storage, integrating cost-efficiency and energy density to meet the demand for stationary applications. Recent efforts have focused on the improvement of electrode materials in aqueous electrolytes, particularly the cycle life and energy reliability of batteries. The anion intercalation chemistry in graphite could be an alternative cathode candidate, often requiring an upper cut-off potential above 4.5 V vs. Li+/Li. Such a potential readily exceeds the electrochemical stability windows of water-based electrolytes. Herein, we provide a progress report and critical comment on the reversible intercalation chemistry in graphite compounds, i.e. , anion and halogen intercalations, for the development of economical, high-energy aqueous rechargeable batteries. In addition, this review focuses on the charge carrier species, their charge storage mechanisms and battery configurations, aiming to provide solutions to solve the remaining key challenges for aqueous batteries. [ABSTRACT FROM AUTHOR]

The use of cobalt-free LiNi 0.5 Mn 1.5 O 4 (LNMO) would provide a great leap forward towards the realization of sustainable lithium-ion batteries. However, the high operating voltage remains to be a great challenge for the cathode/electrolyte stability. Herein, we report a rational material design to address these challenges by carefully tuning the synthesis parameters in order to engineer LNMO crystals with tailored surface facets, providing an exceptional rate capability and improved interfacial stability. The additional introduction of protective TMPO x coatings further enhances the long-term cycling stability, in particular, at elevated cut-off potentials up to 4.95 V, increased temperature of 40 °C, and high dis-/charge rates. As a result of the careful design of the LNMO active material particles, lithium-ion cells employing this material together with Li 4 Ti 5 O 12 anodes provide an excellent rate capability with 80% of the low-rate capacity at fast dis-/charge rates of 10C combined with highly stable cycling at such high rate, as highlighted by a capacity fading of less than 5% after 1000 cycles. [ABSTRACT FROM AUTHOR]

LiNi0.5Mn1.5O4 (LNMO), which has an operating voltage of 4.8 vs Li/Li+ and a theoretical capacity of 147 mAh g−1, is an interesting cathode material for advanced lithium ion batteries. However, electrolyte decomposition at the electrode can gradually decrease the capacity of the battery. In this study, the surface of the LNMO cathode has been modified with phosphoric acid (PA) to improve the capacity of the LNMO/graphite full cell. Modification of LNMO cathodes by PA is confirmed by surface analysis. Additionally, the presence of lithium bis-(oxalato) borate (LiBOB) as an electrolyte additive further enhances the performance of PA modified LNMO/graphite cells. The improved performance of PA modified cathodes and electrolytes containing LiBOB can be attributed to the suppressed Mn and Ni deposition on the anode. Elemental analysis suggests that the Mn and Ni dissolution is significantly reduced compared to unmodified LNMO/graphite cells with standard electrolyte. [ABSTRACT FROM AUTHOR]

Abstract In this work, we report novel room temperature ionic liquid (RTIL)-based electrolytes to be used with high-energy cathode, lithium-rich nickel manganese cobalt oxide (Li[Li 0.2 Mn 0.56 Ni 0.16 Co 0.08 ]O 2 , LiR-NMC) in Li-ion batteries. The physical and electrochemical characteristics of the newly developed materials are thoroughly detailed, also by means of post-cycling electrochemical impedance spectroscopy (EIS) analysis of the resulting lab-scale lithium cells upon long-term, constant-current cycling (>1200 cycles). In addition, an innovative polymer electrolyte is developed encompassing the best performing RTIL-based electrolyte mixture, which is investigated in terms of its physico-chemical features, ion transport and electrochemical behaviour by EIS, cyclic voltammetry and constant-current (galvanostatic) cycling. The polymer electrolyte is obtained via facile, rapid and easily up-scalable UV-induced free radical polymerization (UV curing) technique, being a low-cost and solvent-free approach compared to other existing film formation techniques. The versatile fabrication method along with the use of appropriate materials may turn high-voltage, solid state and ageing resistant batteries into industrial reality in the coming years, as underlined by the excellent electrochemical response of the lithium polymer cell. Highlights • Novel RTIL-based electrolytes for Li-rich nickel manganese cobalt oxide. • Very high ionic conductivity and wide electrochemical stability. • Stable cycling in Li/LiR-NMC cells at 45 °C for > 1200 cycles. • Simple, cheap thermal polymerization approach for Li polymer batteries. • Innovative RTIL-based green polymer electrolytes with safe characteristics. [ABSTRACT FROM AUTHOR]

Abstract Nickel-rich Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 is considered to be the next step forward towards the realization of high-energy lithium-ion batteries and has, thus, attracted intensive attention recently. However, achieving long-term cycling stability at elevated temperatures and voltages still remains a formidable challenge for practical applications. In this work, we successfully synthesized MnPO 4 -coated Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 (MP-NCM) with an advantageously low coating content of only 1 wt% while providing substantially enhanced electrochemical performance and outstanding cycling stability. This improvement is ascribed to the MnPO 4 coating, acting as an ideal protective layer to dramatically reduce the occurring side reactions with the electrolyte, especially at higher temperatures and cut-off voltages. By preventing the direct contact between the cathode active material and the electrolyte, the presence of the coating layer reduces the transition metal dissolution, thus, yielding good structural integrity upon cycling, while its amorphous nature allows for an enhanced apparent lithium ion diffusion, i.e. , lithium de-/insertion kinetics. Additionally, the strong covalent bonding of the PO 4 -group contributes to an increased thermal stability and the high voltage performance of MP-NCM. On the basis of our work, the coating design strategy delivers valuable materials for the practical realization of lithium-ion batteries with superior long-term cycling stability at higher operation temperature and voltage. Graphical abstract Image 1 Highlights • MnPO 4 coated LiNi 0.6 Co 0.2 Mn 0.2 O 2 offers enhanced thermal stability. • The MnPO 4 coating ensures the structural integrity of the active material. • MnPO 4 coating of LiNi 0.6 Co 0.2 Mn 0.2 O 2 enable the use of aqueous binders. • The MnPO 4 coating of LiNi 0.6 Co 0.2 Mn 0.2 O 2 suppresses side reactions with the electrolyte. • MnPO 4 -coated LiNi 0.6 Co 0.2 Mn 0.2 O 2 well performs at elevated temperature and high voltage. [ABSTRACT FROM AUTHOR]

Na 3 V 2 (PO 4 ) 3 (NVP) is a promising cathode material for sodium ion batteries due to the good electrochemical performance in terms of cycling stability and rate capability. However, in order to access this performance a carbon coating is required to enhance the intrinsically poor material's conductivity. Herein, we systematically investigate the role of N -doped carbon (NC) coatings on both the structural and electrochemical properties of NVP materials. NC-coated NVP materials with various nitrogen contents have been rationally synthesized by a novel solid-state method allowing the selective N -doping of the carbon coating. In fact, the N -doping changes the disorder and graphitic character of the carbon layer, strongly impacting the electrochemical performance of the NVP/C composite materials. Results suggest that the appropriate N -doping amount of the carbon leads to highly decreased electrode polarization and excellent cycling stability at high rate, enabling the NVP materials with high energy and power efficiencies. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) are establishing themselves as a low-cost alternative to the widespread lithium-ion technology, a trend that is exemplified by the use of aluminium as anode current collector. In order to be in line with this philosophy, environmentally friendly, abundant and cheap materials need to be used in order to provide a complementary rather than competing battery technology other than lithium-ion. With the same scope in mind, herein we present the structural and electrochemical characterization of P2-type Na x Mg 0.11 Mn 0.89 O 2 material to demonstrate the effectiveness of Mg-doping for the development of future layered cathode materials. Of particular interest is the effect on the long-term cyclability (200 cycles), which has not been reported, yet. As shown in the manuscript, a Mg content as low as 11% in the MO 2 layer leads to a smoothing of the potential profile, very high coulombic efficiencies exceeding 99.5% at 12 mA g −1 and a stable long-term cycling behaviour. [ABSTRACT FROM AUTHOR]

Ni-rich layered oxides such as Li[Ni 0.8 Mn 0.1 Co 0.1 ]O 2 (NMC 811) are highly sensitive towards moisture. Any contact with humidity leads to the formation of surface contaminants, which reflect into an increased overpotential and cause accelerated capacity loss during cycling. This is particularly relevant when considering large-scale processing. Herein, we report a diagnostic set of tools to rapidly assess the extent of such surface contaminants on Ni-rich NMC materials comprising different titration methods, electron microscopy, and the determination of the reversible and irreversible water adsorption. Based on a series of samples subjected to a controlled humidity for varying times, the formation of carbonate and hydroxide species is investigated and correlated to the eventual electrochemical performance in half-cells and full-cells. The results show that even rather short storage times under humid atmosphere lead to substantial water uptake and surface species formation and that the formation of these surface species has a severe impact on the capacity retention in half-cells and graphite||NMC 811 full-cells. [Display omitted] • Development of diagnosis tools for Ni-rich Li-ion cathodes. • Investigation of the impact of humidity exposure during storage. • Warder titration as suitable method for the determination of carbonates. • Verification of the suitability of the diagnosis tools by electrochemical tests. [ABSTRACT FROM AUTHOR]

Abstract: In this manuscript a novel approach to enable aqueous binders for lithium ion battery (LIB) cathodes is reported. Producing LiNi1/3Mn1/3Co1/3O2 (NMC) electrodes using sodium-carboxymethylcellulose (CMC) as a binder and water as a solvent, in fact, results in serious aluminum corrosion during electrode manufacturing due to the high pH of the slurry. In order to prevent the direct contact of the corrosive slurry with aluminum foil, the latter is first coated with a thin carbon layer. The CMC-based electrodes formed on carbon coated aluminum foil show enhanced performance than those made using unprotected aluminum instead. In particular, electrodes using protected aluminum foil are able to deliver a capacity of 126 mAh g−1 at 1C rate, which is rather close to that delivered by polyvinylidene-di-fluoride (PVdF)-based electrode having the same composition. [Copyright &y& Elsevier]

Abstract: Poly(ethylene oxide)-lithium bis(trifluoromethanesulfonyl)imide N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PEO-LiTFSI-Pyr14TFSI)-based 4 V-class composite cathodes, incorporating either Li(Ni1/3Co1/3Mn1/3)O2 or Li(Ni0.8Co0.15Al0.05)O2 were prepared by a hot-pressing process and successively investigated in terms of their morphological, thermal, and electrochemical properties. Thereby, excellent mechanical and thermal properties could be demonstrated for all composite cathodes. The electrochemical performance of truly dry all-solid-state Li/P(EO)10LiTFSI-(Pyr14TFSI)2/composite cathode batteries at temperatures as low as 40 °C revealed high delivered capacities. However, in comparison with LiFePO4, the 4 V-class composite cathodes also indicated much lower capacity retention. In-depth investigations on the interfacial properties of Li(Ni0.8Co0.15Al0.05)O2 composite cathodes revealed a strong dependence on the anodic cut-off potential and the presence of current flow through the cell, whereby different degradation mechanisms could be characterized upon cycling, according to which the finite growth of a surface films at both electrode/polymer electrolyte interfaces inhibited continuous decomposition of the polymer electrolyte even at potentials as high as 4.3 V. Moreover, the presence of Pyr14TFSI in the 4 V-class composite cathodes sustainably reduced the cathode interfacial resistance and presumably diminished the corrosion of the aluminum current collector. [Copyright &y& Elsevier]

Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (PYR14FSI) (1:9 in molar ratio) is successfully tested as electrolyte for the high voltage LiMO2–Li2MnO3 (cathode)/lithium (anode) cells at elevated temperature (40 °C). Compared to conventional electrolytes, such as 1 M LiPF6 solution in the mixed solvent of ethylene and dimethyl carbonate (EC:DMC = 1:1), the use of PYR14FSI–LiTFSI electrolyte results in a net improvement of LiMO2–Li2MnO3 cycling stability while granting comparable initial capacity. In addition, the ionic conductivity of the ionic liquid-based electrolyte at 40 °C is high enough to sustain the excellent rate capability of this cathode material. Li/LiMO2–Li2MnO3 cells delivered initial capacity exceeding 200 mA h g−1 at high current rate (2 C) while retaining 94% of the initial capacity after 100 cycles. Differential capacity versus potential analysis and post-mortem characterization by scanning electron microscope, X-ray diffraction and were carried out to explain the improved performance of LiMO2–Li2MnO3 in the IL-based electrolyte. [ABSTRACT FROM AUTHOR]

Abstract: The self-discharge mechanism of LiNi0.4Mn1.6O4, investigated by electrochemical methods, is mostly attributed to oxidative electrolyte decomposition due to the high lithium (de-)insertion potentials, since the material insertion capacity appears to be fully reversible upon subsequent galvanostatic cycling. A series of 40 different compounds, such as for instance fluorinated ethylene carbonate, 1,3-propane sultone, lithium bis(oxalato)borate (LiBOB), or a variety of ionic liquids, was investigated as suitable electrolyte additives to form a stable LNMO/electrolyte interphase in order to prevent the self-discharge by the continuous oxidative electrolyte decomposition. Among these, only one compound, namely succinic anhydride, revealed to have a beneficial effect on the self-discharge of LNMO based cathodes, while showing an enhanced coulombic efficiency and a decreased capacity loss per cycle. Additionally, the modification of the LNMO particles surface by adding succinic anhydride to the electrolyte was confirmed by performing ex situ SEM and XPS analysis of galvanostatically cycled electrodes. [Copyright &y& Elsevier]

Abstract: In this paper, we investigated the properties of carbon coated lithium sulfide particles prepared following either a dry coating process or a wet coating process, using, respectively, sucrose or polyacrylonitrile (PAN) as carbon source. X-ray diffraction analysis revealed that the crystalline structure of the pristine Li2S was basically preserved upon both coating processes. The dry coating process (Li2S-Csucrose) resulted in Li2S particles covered only partially by smaller carbon particles, whereas the wet coating method (Li2S-CPAN) gave Li2S particles, homogenously decorated with thin carbon flakes. As a result, the cycling performance of Li2S-C based electrodes was significantly improved, particularly for Li2S-CPAN, for which a coulombic efficiency of more than 99.5% was obtained. [Copyright &y& Elsevier]

Abstract: The stability vs. aging of Li2FeSiO4 (LFS) cathode material in fluorine-based electrolytes, especially at elevated temperature, was studied in this work. The LFS powder was initially synthesized using a hydrothermal route and then aged at 60°C for 40 days in LiPF6 and LiBF4-based electrolytes. The residual powder and the electrolyte were investigated afterwards. In the case of LiPF6, a structural and compositional change of LFS to Li2SiF6 was observed by XRD. SEM images confirmed that this change led to a morphology change of the aged material. XPS, EDX and ICP-OES measurements showed a large increase of fluorine content inside the residual powder. NMR investigations indicated an accelerated decomposition of electrolyte in the presence of LFS compared to the electrolyte aged without LFS. Our results suggest a degradation of LFS to Li2SiF6 in the fluorine-based electrolyte at elevated temperatures while the electrolyte decomposition is accelerated. [Copyright &y& Elsevier]

Abstract: The cycle behaviour and rate performance of solid-state Li/LiFePO4 polymer electrolyte batteries incorporating the N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR13TFSI) room temperature ionic liquid (IL) into the P(EO)20LiTFSI electrolyte and the cathode have been investigated at 40°C. The ionic conductivity of the P(EO)20LiTFSI+PYR13TFSI polymer electrolyte was about 6×10−4 Scm−1 at 40°C for a PYR13 +/Li+ mole ratio of 1.73. Li/LiFePO4 batteries retained about 86% of their initial discharge capacity (127mAhg−1) after 240 continuous cycles and showed excellent reversible cyclability with a capacity fade lower than 0.06% per cycle over about 500 cycles at various current densities. In addition, the Li/LiFePO4 batteries exhibited some discharge capability at high currents up to 1.52mAcm−2 (2C) at 40°C which is very significant for a lithium metal-polymer electrolyte (solvent-free) battery systems. The addition of the IL to lithium metal-polymer electrolyte batteries has resulted in a very promising improvement in performance at moderate temperatures. [Copyright &y& Elsevier]

A highly concentrated solution of potassium, lithium and zinc acetate is proposed as green "Water-in-Salt" electrolyte (WiSE). In this halide-free electrolyte, investigated by classical Molecular Dynamics simulations, differential scanning calorimetry (DSC) and Raman spectroscopy, the water molecules are coordinated by the acetate anion as well as the various cations. As a result of the strong coordination of water molecules, the WiSE enables outstanding zinc (Zn) plating/stripping average Coulombic efficiency (CE) (99.6%) and long-term cycling stability. Dual ion cells using this electrolyte and featuring the Zn metal anode and either LiFePO 4 (LFP) or spinel LiMn 2 O 4 (LMO)-based cathodes deliver discharge capacity of 155 mA h g−1 and 121 mA h g−1 at 0.05C, respectively. The Zn/LFP cells demonstrate better cycling stability compared to Zn/LMO, which is attributed to the more stable crystal structure of LFP. Image 1 • Non fluorinated Water in Salt Electrolytes (WiSEs) for sustainable Zn batteries. • MD simulations help investigating the solvation-sheath structure of WiSEs. • Effect of WiSEs on the plating/stripping behavior of Zn anodes. • Effect of the cathode on the cyclability of Zn metal cells employing WiSE. [ABSTRACT FROM AUTHOR]

Herein we address the key challenge towards the practical use of high-voltage lithium-ion cathode materials, i.e., the insufficient stability of the electrolyte towards oxidation. The transition metals in such materials, especially nickel, catalyze the decomposition reaction of the electrolyte, ultimately leading to poor cycling stability and rapid fading of the battery. To tackle this challenge, a new combination of electrolyte additives is introduced, targeting stabilized electrode/electrolyte interfaces and interphases for both the anode and cathode. The results show that the synergistic effect of tris(trimethylsilyl) phosphite (TTSPi) and bis(2,2,2-trifluoroethyl) carbonate (TFEC) can significantly improve the performance of cathode half-cells and also of lithium-ion full-cells with a cell voltage higher than 4.5 V. Cells using both TTSPi and TFEC as additives show greatly enhanced cycling stability, increased capacity, and improved coulombic efficiency, which can be even further improved when adding also lithium bis(oxalato)borate. Image 1 • Design of an electrolyte composition for high-voltage cathodes. • Enhanced performance for 5 V cathodes and graphite anodes. • In-depth analysis of the SEI and CEI in half-cells and full-cells. • Synergistic effect of TTSPi and TFEC for high-voltage cathodes and graphite anodes. • Further improvement by adding also LiBOB. [ABSTRACT FROM AUTHOR]