Lithium sulfur battery exploiting material design and electrolyte chemistry: 3D graphene framework and diglyme solution

Herein we investigate a lithium sulfur battery suitably combining alternative cathode design and relatively safe, highly conductive electrolyte. The composite cathode is formed by infiltrating sulfur in a N-doped 3D graphene framework prepared by a microwave assisted solvothermal approach, while the electrolyte is obtained by dissolving lithium bis(trifluoromethane)sulfonimide (LiTFSI) in diethylene glycol dimethyl ether (DEGDME), and upgraded by addition of lithium nitrate (LiNO3) as a film forming agent. The particular structure of the composite cathode, studied in this work by employing various techniques, well enhances the lithium-sulfur electrochemical process leading to very stable cycling trend and specific capacity ranging from 1000 mAh g−1 at the highest rate to 1400 mAh g−1 at the lowest one. The low resistance of the electrode/electrolyte interphase, driven by an enhanced electrode design and a suitable electrolyte, is considered one of the main reasons for the high performance which may be of interest for achieving a promising lithium-sulfur battery. Furthermore, the study reveals a key bonus of the cell represented by the low flammability of the diglyme electrolyte, while comparable conductivity and interface resistance, with respect to the most conventional solution used for the lithium sulfur cell

IST Austria Technical Report

With the lithium-ion technology approaching its intrinsic limit with graphite-based anodes, lithium metal is recently receiving renewed interest from the battery community as potential high capacity anode for next-generation rechargeable batteries. In this focus paper, we review the main advances in this field since the first attempts in the mid-1970s. Strategies for enabling reversible cycling and avoiding dendrite growth are thoroughly discussed, including specific applications in all-solid-state (polymeric and inorganic), Lithium-sulphur and Li-O2 (air) batteries. A particular attention is paid to review recent developments in regard of prototype manufacturing and current state-ofthe-art of these battery technologies with respect to the 2030 targets of the EU Integrated Strategic Energy Technology Plan (SET-Plan) Action 7

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

2021 roadmap on lithium sulfur batteries

Abstract: Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance the commercial prospects of the technology and benefit from the economies of scale felt by Li-ion cells, including improving both the rate performance and longevity of cells. To address these challenges, the Faraday Institution, the UK’s independent institute for electrochemical energy storage science and technology, launched the Lithium Sulfur Technology Accelerator (LiSTAR) programme in October 2019. This Roadmap, authored by researchers and partners of the LiSTAR programme, is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the LiSTAR consortium. In compiling this Roadmap we hope to aid the development of the wider Li–S research community, providing a guide for academia, industry, government and funding agencies in this important and rapidly developing research space

Insight on the Enhanced Reversibility of a Multimetal Layered Oxide for Sodium-Ion Battery

Sodium-ion layered cathodes range along a vast variety of structures and chemical compositions that influence the physical-chemical characteristics and the electrochemical features in battery. In this work, we show that the synergistic effects of various metals, enhanced structure, and optimal morphology of Na0.48Al0.03Co0.18Ni0.18Mn0.47O2 material lead to remarkable reversibility in a sodium cell. X-ray diffraction refinement evidences that the electrode has a P3/P2-type layered structure, whereas scanning electron microscopy study shows a morphology consisting of primary layers with nanometric thickness regularly stacked into uniform micrometric particles. In-depth investigation combining ex situ X-ray diffraction, galvanostatic intermittent titration, and voltammetry measurements reveals solid-solution Na+ intercalation into the layered oxide between 1.4 and 4.6 V versus Na+/Na with relevant lattice stability. Furthermore, the study shows the absence of phase transitions during Na+ exchange within the material framework, which advantageously leads to enhanced reversibility, benefiting from minor lattice change upon Na+ intercalation, fast diffusion, improved electrode/electrolyte interphase, and smooth voltage profile. Hence, the electrode delivers a maximum capacity of about 175 mAh g-1 with suitable cycling stability and a Coulombic efficiency approaching 99% in a sodium cell. Therefore, we believe that the study reported herein may shed light on important characteristics of this attractive class of electrodes, allowing efficient operation in next-generation sodium-ion batteries

Lithium-Ion Battery Based on LiMn0.5Fe0.5PO4 Cathode and Lithium Alloying Anode

Polyanion framework olivine materials have attracted large attention as cathodes in LIBs. Recently, the attention of the scientific community has been focused on the substitution of iron by manganese, cobalt or nickel within the olivine lattice [1]. Indeed, Mn3+/Mn2+, Co3+/Co2+ and Ni3+/Ni2+ couples show increasing redox potentials compared to Fe3+/Fe2+, thus leading to an increased energy density. However, the latter two exhibit redox potential of about 4.8 and 5.2 V vs. Li+/Li, respectively, i.e. a value exceeding the conventional carbonate-based electrolytes stability limit [2]. LiMnPO4 has instead an operating voltage of about 4.1 V vs. Li+/Li, still within the working electrochemical window of conventional electrolytes, thus leading to a theoretical energy density of about 700 Wh kg-1 [3]. LiMnPO4 suffers from poor electric conductivity in comparison to LiFePO4 [4]. Several approaches have been studied to improve LiMnPO4 electrochemical activity in lithium cell. Incorporation of conductive additives, such as carbon, by post-synthesis ball milling or formation of a carbon layer on particle surface can increase the electronic conductivity [5, 6]. Significant decrease of the lithium diffusion pathway and consequent conductivity increase may be reached by reduction of particle size by proper synthetic procedures leading to nano-morphologies [7, 8]. Soft-chemistry methods allow more controlled tailoring of morphologies and size than the conventional solid-state approaches [9]. In particular, hydro- and solvo-thermal methods are simple techniques allowing the precipitation of olivines at low temperature and controlled crystal growth [10]. Further improvement of the cathode performance may be reached by mixed compositions, LiMn1-xFexPO4. Iron incorporation in the olivine lattice has proven to enhance the electrochemical activity of the Mn3+/Mn2+ redox reaction by increasing both electronic and ionic conductivity, and by reducing lattice strain due to Jahn-Teller active ion Mn3+ [11, 12]. Herein we report the synthesis and characterization of LiMnPO4, LiFePO4 and mixed LiMn0.5Fe0.5PO4 materials through solvothermal approach. Careful analysis of the electrochemical properties by potentiodynamic cycling with galvanostatic acceleration and galvanostatic cycling techniques were carried out in order to investigate the features of the Fe3+/Fe2+ and Mn3+/Mn2+ redox couples in the olivine structure. In addition, an advanced lithium-ion battery formed by combining a LiMn0.5Fe0.5PO4 cathode with a Sn-C anode is reported. The figure shows the galvanostatic cycling results of a Sn-C/LiMn0.5Fe0.5PO4 cell

Lithium Metal Battery Using LiFe0.5Mn0.5PO4Olivine Cathode and Pyrrolidinium-Based Ionic Liquid Electrolyte

Ionic liquids (ILs) represent the most suitable electrolyte media for a safe application in high-energy lithium metal batteries because of their remarkable thermal stability promoted by the room-temperature molten salt nature. In this work, we exploit this favorable characteristic by combining a pyrrolidinium-based electrolyte and a LiFe0.5Mn0.5PO4mixed olivine cathode in a lithium metal cell. The IL solution, namely N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) dissolving LiTFSI, is designed as viscous electrolyte, particularly suited for cells operating at temperatures higher than 40 °C, as demonstrated by electrochemical impedance spectroscopy. The olivine electrode, characterized by remarkable structural stability at high temperature, is studied in the lithium metal cell using the Pyr14TFSI-LiTFSI medium above the room temperature. The Li/Pyr14TFSI-LiTFSI/LiFe0.5Mn0.5PO4cell delivers a capacity of about 100 mA h g-1through two voltage plateaus at about 3.5 and 4.1 V, ascribed to the iron and manganese redox reaction, respectively. The cycling stability, satisfactory levels of the energy density, and a relevant safety content suggest the cell studied herein as a viable energy storage system for future applications

Lithium Transport Properties in LiMn1αFeαPO4 Olivine Cathodes

We report a comparative study of the electrochemical lithium diffusion properties within the olivine structure of LiMn0.5Fe0.5PO4, LiFePO4, and LiMnPO4 materials prepared by the solvothermal pathway. The study includes careful analysis performed by potentiodynamic cycling with galvanostatic acceleration (PCGA), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and the galvanostatic intermittent titration technique (GITT), carried out in order to investigate the features of the Fe3+/Fe2+ and Mn3+/Mn2+ redox processes and the lithium ion transport within the olivine structure. The electrochemical investigation reveals a shift of the redox potential of Fe3+/Fe2+ and Mn3+/Mn2+ couples toward higher and lower values, respectively, in LiMn0.5Fe0.5PO4 with respect to the bare materials. Interestingly, the study shows the dependence of the lithium diffusion coefficients on the state of charge of the materials as well as on the adopted technique. Accordingly, CV leads to lithium diffusion coefficients of the order of 10−12 cm2 s−1 for LiMnPO4, 10−9 cm2 s−1 for LiFePO4, and 10−11 cm2 s−1 for LiMn0.5Fe0.5PO4. EIS mainly indicates lower values of lithium diffusion coefficients, i.e., 10−13 cm2 s−1 for LiMnPO4, 10−12 cm2 s−1 for LiFePO4, and 10−13 cm2 s−1 for LiMn0.5Fe0.5PO4. GITT provides a wide range of Li+ diffusion coefficient, depending on the Li1−xMePO4 stoichiometry, that is, 10−14−10−10 cm2 s−1 for LiMnPO4 and LiFePO4 and 10−13−10−10 cm2 s−1 for LiMn0.5Fe0.5PO4. The wide diffusion coefficient window obtained by changing the state of charge and the adopted technique sheds light on the complex trend of the lithium diffusion in olivines and indicates that the technique may actually influence the materials evaluation

New lithium ion batteries exploiting conversion/alloying anode and LiFe0.25Mn0.5Co0.25PO4 olivine cathode

New Li-ion cells are formed by combining a LiFe0.25Mn0.5Co0.25PO4 olivine cathode either with Sn-Fe2O3-C or with Sn-C composite anodes. These active materials exhibit electrochemical properties very attractive in view of practical use, including the higher working voltage of the LiFe0.25Mn0.5Co0.25PO4 cathode with respect to conventional LiFePO4, as well as the remarkable capacity and rate capability of Sn-Fe2O3-C and Sn-C anodes. The stable electrode/electrolyte interfaces, demonstrated by electrochemical impedance spectroscopy, along with proper mass balancing and anode pre-lithiation, allow stable galvanostatic cycling of the full cells. The two batteries, namely Sn-Fe2O3-C/LiFe0.25Mn0.5Co0.25PO4 and Sn-C/LiFe0.25Mn0.5Co0.25PO4, reversibly operate revealing promising electrochemical features in terms of delivered capacity, working voltage and stability, thus suggesting these electrodes combinations as suitable alternatives for an efficient energy storage

Electrochemical features of LiMnPO4 olivine prepared by sol-gel pathway

LiMnPO4 is a potential cathode for lithium-ion battery of high thermal stability, low cost, environmental sustainability and high theoretical energy density. However, this intriguing olivine material suffers from intrinsic sluggish kinetics of lithium (de-)insertion, which limits the reversible reaction in practical lithium cells. Herein we report a careful study of the impedance features of LiMnPO4 during electrochemical reaction in lithium cell. The LiMnPO4 material is prepared by sol-gel method and fully characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The material shows suitable galvanostatic cycling with a working voltage of about 4.1 V, which is higher than the 3.5 V value expected from the most common olivine material, i.e., LiFePO4. Hence, electrochemical impedance spectroscopy (EIS) is used to study the lithium (de-)insertion within the LiMnPO4 structure. The results indicate an impedance behavior depending on the state of charge and a lithium diffusion coefficient trend slightly decreasing during cell operation within the 10−14 − 10−13 cm2 s−1 range. The electrochemical study in lithium cell reveals remarkable enhancement of the electrode kinetics at 70 °C, which suggests preferred application of LiMnPO4 materials at the higher temperatures