Structural and thermal properties of Na₂Mn(SO₄)₂·4H₂O and Na₂Ni(SO₄)₂·10H₂O

The title compounds were prepared via a wet chemistry route and their crystal structures were determined from single crystal X-ray diffraction data. Na2Mn(SO4)2·4H2O crystallizes with a monoclinic symmetry, space group P21/c, with a = 5.5415(2), b = 8.3447(3), c = 11.2281(3) Å, β = 100.172(1)°, V = 511.05(3) Å3 and Z = 2. Na2Ni(SO4)2·10H2O also crystallizes with a monoclinic symmetry, space group P21/c, with a = 12.5050(8), b = 6.4812(4), c = 10.0210(6) Å, β = 106.138(2)°, V = 780.17(8) Å3 and Z = 2. Na2Mn(SO4)2·4H2O is a new member of the blödite family of compounds, whereas Na2Ni(SO4)2·10H2O is isostructural with Na2Mg(SO4)2·10H2O. The structure of Na2Mn(SO4)2·4H2O is built up of [Mn(SO4)2(H2O)4]2− building blocks connected through moderate O–H⋯O hydrogen bonds with the sodium atoms occupying the large tunnels along the a axis and the manganese atom lying on an inversion center, whereas the structure of Na2Ni(SO4)2·10H2O is built up of [Ni(H2O)6]2+ and [Na2(SO4)2(H2O)4]2− layers. These layers which are parallel to the (100) plane are interconnected through moderate O–H⋯O hydrogen bonds. The thermal gravimetric- and the powder X-ray diffraction-analyzes showed that only the nickel phase was almost pure. At a temperature above 300 °C, all the water molecules evaporated and a structural phase transition from P21/c-Na2Ni(SO4)2·10H2O to C2/c-Na2Ni(SO4)2 was observed. C2/c-Na2Ni(SO4)2 is thermally more stable than Na2Fe(SO4)2 and therefore it would be suitable as the positive electrode for sodium ion batteries if a stable electrolyte at high voltage is developed. Other information Published in: RSC Advances License: https://creativecommons.org/licenses/by-nc/3.0 See article on publisher's website: http://dx.doi.org/10.1039/d0ra00301h </p

Lithium-Ion Battery Power Performance Assessment for the Climb Step of an Electric Vertical Takeoff and Landing (eVTOL) Application

High power is a critical requirement of lithium-ion batteries designed to satisfy the load profiles of advanced air mobility. Here, we simulate the initial takeoff step of electric vertical takeoff and landing (eVTOL) vehicles powered by a lithium-ion battery that is subjected to an intense 15C discharge pulse at the beginning of the discharge cycle followed by a subsequent low-rate discharge. We conducted extensive electrochemical testing to assess the long-term stability of a lithium-ion battery under these high-strain conditions. The main finding is that despite the performance recovery observed at low rates, the reapplication of high rates leads to drastic cell failure. While the results highlight the eVTOL battery longevity challenge, the findings also emphasize the need for tailored battery chemistry designs for eVTOL applications to address both anode plating and cathode instability. In addition, innovative second-use strategies would be paramount upon completion of the eVTOL services

Improving Contact Impedance via Electrochemical Pulses Applied to Lithium–Solid Electrolyte Interface in Solid-State Batteries

Stabilizing interfaces in solid-state batteries (SSBs) is crucial for development of high energy density batteries. In this work, we report a facile electrochemical protocol to improve the interfacial impedance and contact at the interface of Li | Li6.25Al0.25La3Zr2O12 (LALZO). Application of short duration, high-voltage pulses to poorly formed interfaces leads to lower contact impedance. It is found that the local high current density that results from these pulses at the vicinity of the interfacial pores can lead to a better contact between Li and LALZO because of local Joule heating, as supported by theoretical simulations. The pulse technique, which has also been applied to a Li | Li6.4La3Zr1.4Ta0.6O12 (LLZTO) | LiNi0.6Mn0.2Co0.2O2 (NMC622) cell, results in remarkable reduction of the charge-transfer resistance. Ex situ characterizations, which include X-ray photoelectron spectroscopy and scanning electron microscopy techniques, reveal that there is no detrimental effects of the pulse on cathode and solid electrolyte bulks and interfaces. This electrochemical pulse technique sheds light on a facile, nondestructive method that has the potential to significantly improve the interfacial contacts in a solid-state battery configuration

Tailoring of the Anti-Perovskite Solid Electrolytes at the Grain-Scale

The development of thin, dense, defect-free solid electrolyte films is key for achieving practical and commercially viable solid-state batteries. Herein, we showcase a facile processing pathway for antiperovskite (Li2OHCl) solid electrolyte materials that can yield films/pellets with very high densities (∼100%) and higher conductivities compared with conventional uniaxially pressed pellets. We have also achieved close to 50% improvement in the critical current density of the material and an improved lithiophilicity due to the surface nitrogen enrichment of the processed pellets. Distribution of relaxation time analysis supports the contributions from “faster” transport mechanisms for the antiperovskite films/pellets developed using the new protocol. Overall, the results highlight the feasibility of our new processing pathway for engineering antiperovskite solid electrolytes at the grain scale as a highly desirable approach for practical all-solid-state batteries

Differences in the Interfacial Mechanical Properties of Thiophosphate and Argyrodite Solid Electrolytes and Their Composites

Interfacial mechanics are a significant contributor to the performance and degradation of solid-state batteries. Spatially resolved measurements of interfacial properties are extremely important to effectively model and understand the electrochemical behavior. Herein, we report the interfacial properties of thiophosphate (Li3PS4)- and argyrodite (Li6PS5Cl)-type solid electrolytes. Using atomic force microscopy, we showcase the differences in the surface morphology as well as adhesion of these materials. We also investigate solvent-less processing of hybrid electrolytes using UV-assisted curing. Physical, chemical, and structural characterizations of the materials highlight the differences in the surface morphology, chemical makeup, and distribution of the inorganic phases between the argyrodite and thiophosphate solid electrolytes

The Role of Isostatic Pressing in Large-Scale Production of Solid-State Batteries

Scalable processing of solid-state battery (SSB) components and their integration is a key bottleneck toward the practical deployment of these systems. In the case of a complex system like a SSB, it becomes increasingly vital to envision, develop, and streamline production systems that can handle different materials, form factors, and chemistries as well as processing conditions. Herein, we highlight isostatic pressing (ISP) as a versatile processing platform for large-scale production of the currently most promising solid electrolyte materials. We briefly summarize the development of ISP techniques as well as the processing methods and windows accessible. Subsequently, we discuss recent reports on SSBs that leverage ISP techniques and their impact on the electrochemical performance of the systems. Finally, we also provide a techno-economic analysis for implementing ISP at scale along with some key perspectives, challenges, and future directions for large-scale production of SSB components and integration

The Role of Isostatic Pressing in Large-Scale Production of Solid-State Batteries

Scalable processing of solid-state battery (SSB) components and their integration is a key bottleneck toward the practical deployment of these systems. In the case of a complex system like a SSB, it becomes increasingly vital to envision, develop, and streamline production systems that can handle different materials, form factors, and chemistries as well as processing conditions. Herein, we highlight isostatic pressing (ISP) as a versatile processing platform for large-scale production of the currently most promising solid electrolyte materials. We briefly summarize the development of ISP techniques as well as the processing methods and windows accessible. Subsequently, we discuss recent reports on SSBs that leverage ISP techniques and their impact on the electrochemical performance of the systems. Finally, we also provide a techno-economic analysis for implementing ISP at scale along with some key perspectives, challenges, and future directions for large-scale production of SSB components and integration

The Role of Isostatic Pressing in Large-Scale Production of Solid-State Batteries

Scalable processing of solid-state battery (SSB) components and their integration is a key bottleneck toward the practical deployment of these systems. In the case of a complex system like a SSB, it becomes increasingly vital to envision, develop, and streamline production systems that can handle different materials, form factors, and chemistries as well as processing conditions. Herein, we highlight isostatic pressing (ISP) as a versatile processing platform for large-scale production of the currently most promising solid electrolyte materials. We briefly summarize the development of ISP techniques as well as the processing methods and windows accessible. Subsequently, we discuss recent reports on SSBs that leverage ISP techniques and their impact on the electrochemical performance of the systems. Finally, we also provide a techno-economic analysis for implementing ISP at scale along with some key perspectives, challenges, and future directions for large-scale production of SSB components and integration

Understanding the Origin of the Ultrahigh Rate Performance of a SiO₂‑Modified LiNi_0.5Mn_1.5O₄ Cathode for Lithium-Ion Batteries

LiNi0.5Mn1.5O4 (LNMO) is one of the most promising cathode materials for next-generation lithium-ion batteries for rapid charging–discharging applications. The surfaces of LNMO samples are coated with different amounts (0.5–2.0 wt %) of silica (SiO2) using a cost-effective and scalable ball milling process, and the surface-modified samples shows excellent electrochemical stability with conventional liquid electrolyte. The advantages of this coating are demonstrated by the improved electrochemical performances at ambient and elevated temperatures (25 and 55 °C) using half- and full-cell configurations. The solid electrolyte interface (SEI) and coating properties have been highlighted by ex situ TEM analysis, which indicates the close attachment and good wetting of the SiO2 layer with the LNMO active particles. Importantly, the 1 wt % SiO2-coated material cycled at 10, 40, and 80 C rates for 400 cycles exhibits excellent cycling stability with capacity retentions of 96.7, 87.9, and 82.4%, respectively. The 1 wt % SiO2-coated material also shows excellent cycling stability when charged at 6 C (10 min.) and discharged at C/3 for 500 cycles. The interfacial resistances of the SiO2-coated LiNi0.5Mn1.5O4 is found to be much lower compared to bare material and does not considerably increase with the amount of coating. Overall, the scalable and cost-effective strategy of SiO2 coating applied to LiNi0.5Mn1.5O4 lowers the interfacial charge transfer resistance and enables the materials to be suitable for extremely fast-charging electric vehicle battery applications