A 3.2 V Binary Layered Oxide Cathode for Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) can offer high energy density, cyclability, and operational safety while being economical due to the natural abundance of potassium. Utilizing graphite as an anode, suitable cathodes can realize full cells. Searching for potential cathodes, this work introduces P3-type KNiMnO layered oxide as a potential candidate synthesized by a simple solid-state method.

Single-Crystal P2-NaMnNiO Cathode Material with Improved Cycling Stability for Sodium-Ion Batteries.

Layered oxides constitute one of the most promising cathode materials classes for large-scale sodium-ion batteries because of their high specific capacity, scalable synthesis, and low cost. However, their practical use is limited by their low energy density, physicochemical instability, and poor cycling stability. Aiming to mitigate these shortcomings, in this work, we synthesized polycrystalline (PC) and single-crystal (SC) P2-type NaMnNiO (NMNO) cathode materials through a solid-state route and evaluated their physicochemical and electrochemical performance.

Role of Co Content on the Electrode Properties of P3-Type KMnCoO Potassium Insertion Materials.

Potassium-ion batteries are widely being pursued as potential candidates for stationary (grid) storage, where energy dense K insertion cathodes are central to economic and energy efficient operation. To develop robust K-based cathodes, it is key to correlate their underlying electronic states to the final electrochemical performance. Here, we report the synthesis and structure-electrochemical property correlation in P3-type KMnCoO binary layered oxide cathodes.

Greener, Safer and Better Performing Aqueous Binder for Positive Electrode Manufacturing of Sodium Ion Batteries.

P2-type cobalt-free MnNi-based layered oxides are promising cathode materials for sodium-ion batteries (SIBs) due to their high reversible capacity and well chemical stability. However, the phase transformations during repeated (dis)charge steps lead to rapid capacity decay and deteriorated Na diffusion kinetics. Moreover, the electrode manufacturing based on polyvinylidene difluoride (PVDF) binder system has been reported with severely defluorination issue as well as the energy intensive and expensive process due to the use of toxic and volatile N-methyl-2-pyrrolidone (NMP) solvent.

Iron-based fluorophosphate NaFePOF as a cathode for aqueous zinc-ion batteries.

Aqueous zinc-ion batteries form a key post-Li-ion batteries to cater the rising demand for grid storage. Fe-based compounds can be used as economical cathodes for zinc-ion batteries. Herein, we explored iron-based flourophosphate as a potential polyanionic cathode.

Evaluation of P3-Type Layered Oxides as K-Ion Battery Cathodes.

Given the increasing energy storage demands and limited natural resources of Li, K-ion batteries (KIBs) could be promising next-generation systems having natural abundance, similar chemistry, and energy density. Here, we have investigated the P3-type KTMO (where TM = Ti, V, Cr, Mn, Co, or Ni) systems using density functional theory calculations as potential positive intercalation electrodes (or cathodes) for KIBs. Specifically, we have identified ground-state configurations and calculated the average topotactic voltages, electronic structures, on-site magnetic moments, and thermodynamic stabilities of all P3-KTMO compositions and their corresponding depotassiated P3-TMO frameworks.

Zinc-Substituted Cobalt Phosphate [ZnCo(PO)] as a Bifunctional Electrocatalyst.

Development of highly efficient, earth-abundant, and stable bifunctional electrocatalysts is pivotal for designing viable next-generation metal-air batteries. Cobalt-based phosphates provide a treasure house to design electrocatalysts, with a wide range of cation substitutions to further enhance their electrocatalytic activity. In particular, phosphates with distorted geometry show favorable binding efficiency toward water molecules with low overpotential.

Probing Capacity Trends in MLiTiO Lithium-Ion Battery Anodes Using Calorimetric Studies.

Due to higher packing density, lower working potential, and area specific impedance, the MLiTiO (M = 2Na, Sr, Ba, and Pb) titanate family is a potential alternative to zero-strain LiTiO anodes used commercially in Li-ion batteries. However, the exact lithiation mechanism in these compounds remains unclear. Despite its structural similarity, MLiTiO behaves differently depending on charge and size of the metal ion, hosting 1.

First principles investigation of anionic redox in bisulfate lithium battery cathodes.

The search for an alternative high-voltage polyanionic cathode material for Li-ion batteries is vital to improve the energy densities beyond the state-of-the-art, where sulfate frameworks form an important class of high-voltage cathode materials due to the strong inductive effect of the S ion. Here, we have investigated the mechanism of cationic and/or anionic redox in LiM(SO) frameworks (M = Mn, Fe, Co, and Ni and 0 ≤ ≤ 2) using density functional calculations. Specifically, we have used a combination of Hubbard corrected strongly constrained and appropriately normed (SCAN+) and generalized gradient approximation (GGA+) functionals to explore the thermodynamic (polymorph stability), electrochemical (intercalation voltage), geometric (bond lengths), and electronic (band gaps, magnetic moments, charge populations, ) properties of the bisulfate frameworks considered.

Pyrophosphate NaCoPO Polymorphs as Efficient Bifunctional Oxygen Electrocatalysts for Zinc-Air Batteries.

Developing earth-abundant low-cost bifunctional oxygen electrocatalysts is a key approach to realizing efficient energy storage and conversion. By exploring Co-based sodium battery materials, here we have unveiled nanostructured pyrophosphate NaCoPO polymorphs displaying efficient bifunctional electrocatalytic activity. While the orthorhombic polymorph (-NCPy) has superior oxygen evolution reaction (OER) activity, the triclinic polymorph (-NCPy) delivers better oxygen reduction reaction (ORR) activity.

Facile synthesis and phase stability of Cu-based NaCu(SO)·HO ( = 0-2) sulfate minerals as conversion type battery electrodes.

Mineral exploration forms a key approach for unveiling functional battery electrode materials. The synthetic preparation of naturally found minerals and their derivatives can aid in designing of new electrodes. Herein, saranchinaite NaCu(SO) and its hydrated derivative kröhnkite NaCu(SO)·2HO bisulfate minerals have been prepared using a facile spray drying route for the first time.

Manganese-Based Tunnel-Type Cathode Materials for Secondary Li-Ion and K-Ion Batteries.

The rational design of novel cathode materials remains a key pursuit in the development of (post) Li-ion batteries. Considering the relative ionic and Stokes radii and open frameworks with large tunnels, Na-based compounds can act as versatile cathodes for monovalent Li-ion and post-Li-ion batteries. Here, tunnel-type sodium insertion material NaMnO is demonstrated as an intercalation host for Li-ion and K-ion batteries.

Potassium Cobalt Pyrophosphate as a Nonprecious Bifunctional Electrocatalyst for Zinc-Air Batteries.

Economic and sustainable (ecological) energy storage forms a major pillar of the global energy sector. Bifunctional electrocatalysts, based on oxygen electrolysis, play a key role in the development of rechargeable metal-air batteries. Pursuing precious metal-free economic catalysts, here, we report KCoPO pyrophosphate as a robust cathode for secondary zinc-air batteries with efficient oxygen evolution and oxygen reduction (OER||ORR) activity.

An overview of hydroxy-based polyanionic cathode insertion materials for metal-ion batteries.

Rechargeable batteries based on Li-ion and post Li-ion chemistry have come a long way since their inception in the early 1980s. The last four decades have witnessed steady development and discovery of myriads of cathode materials taking into account their processing, economy, and performance along with ecological sustainability. Though oxides rule the battery sector with their high energy and power density, polyanionic insertion compounds work as gold mines for designing insertion compounds with rich structural diversity leading to tuneable redox potential coupled with high structural/chemical/thermal stability.

Crystal and Magnetic Structures of Monoclinic FeOHSO.

The crystal and magnetic structures and properties of the monoclinic form of the iron hydroxysulfate FeOHSO were investigated by magnetometry and neutron powder diffraction. The space group 2/ was confirmed, and the proton position was located close to that predicted by calculations. The collinear antiferromagnetic (0,0,0) structure forming below the Néel temperature ∼ 125 K is described by the 2'/' (No.

Cobalt Metaphosphates as Economic Bifunctional Electrocatalysts for Hybrid Sodium-Air Batteries.

Bifunctional electrocatalysts are pre-eminent to achieve high capacity, cycling stability, and high Coulombic efficiency for rechargeable hybrid sodium-air batteries. The current work introduces metaphosphate (Na)KCo(PO) nanostructures as noble metal-free bifunctional electrocatalysts suitable for the rechargeable aqueous sodium-air battery. Prepared by the scalable solution combustion method, the metaphosphate class of (Na)KCo(PO) with spherical morphology exhibited robust oxygen reduction as well as evolution activity similar to the state-of-the-art catalysts.

The design of zinc-substituted cobalt (pyro)phosphates as efficient bifunctional electrocatalysts for zinc-air batteries.

In an effort to rationally design economic electrocatalysts, zinc-substituted cobalt phosphate and pyrophosphate were prepared using facile template-free combustion synthesis. They act as efficient stable bifunctional electrocatalysts due to the tuning of oxygen affinity by zinc substitution and catalytically active cobalt sites. Exploiting their bifunctional activity, these cobalt (pyro)phosphates were incorporated into a zinc-air battery in an alkaline electrolyte.

Iron-Based Mixed Phosphate NaFe(PO)PO Thin Films for Sodium-Ion Microbatteries.

Iron-based polyanionic materials can be exploited to realize low cost, durable, and safe cathodes for both bulk and thin film sodium-ion batteries. Herein, we report pulsed laser deposited mixed phosphate NaFe(PO)PO as a positive electrode for thin film sodium-ion microbatteries. The bulk material and thin films of NaFe(PO)PO are employed by solution combustion synthesis (SCS) and the pulsed laser deposition (PLD) technique, respectively.

P3-type layered KMnCoO: a novel cathode material for potassium-ion batteries.

P3-type layered KMnCoO was synthesized using a solid-state method. By stabilising into a rhombohedral structure [s.g.

Polymorphism and Temperature-Induced Phase Transitions of NaCoPO.

Polymorphism and temperature-induced phase transitions of NaCoPO were studied by in situ neutron powder diffraction and complemented by ab initio calculations to reconcile previous reports of its three polymorphs. We show that the "blue" form prepared at 873 K exists at room temperature in the orthorhombic 2 (= 2) phase, which transforms via a first-order transition to the tetragonal form at the temperature close to room temperature (∼335 K). Just above the transition, the tetragonal form is likely incommensurately modulated with the modulation vanishing at ∼423 K.

NaMnPO polymorphs as efficient bifunctional catalysts for oxygen reduction and oxygen evolution reactions.

In order to design earth-abundant low cost electrocatalysts, this communication exploits polymorphism in Na2MnP2O7 pyrophosphate sodium insertion materials. Two polymorphs of Na2MnP2O7 have been prepared with a short annealing duration of 30 minutes. These scalable materials exhibit efficient bifunctional electrocatalytic activity stemming from the Mn redox centre and robust structural framework.

Cobalt and Nickel Phosphates as Multifunctional Air-Cathodes for Rechargeable Hybrid Sodium-Air Battery Applications.

Noble-metal-free bifunctional electrocatalysts are indispensable to realize low-cost and energy-efficient rechargeable metal-air batteries. In addition, power density, energy density, and cycle life of these metal-air batteries can be improved further by utilizing the fast faradaic reactions of metal ions in the catalyst layer together with the oxygen evolution/reduction reactions (OER/ORR) for charge storage. In this work, we propose mixed metal phosphates of nickel and cobalt, NiCo(PO) ( = 0,1, 1.

Sodium Cobalt Metaphosphate as an Efficient Oxygen Evolution Reaction Catalyst in Alkaline Solution.

Sodium cobalt metaphosphate [NaCo(PO ) ] has CoO octahedra (CoO ) and shows superior oxygen evolution reaction (OER) activity in alkaline solution, comparable with the state-of-the-art precious-metal RuO catalyst. OER catalysts of this metaphosphate are prepared by combustion (Cb) and solid-state (SS) methods. The combustion-assisted method offers a facile synthesis and one-step carbon composite formation.

Cubic Sodium Cobalt Metaphosphate [NaCo(PO)] as a Cathode Material for Sodium Ion Batteries.

Cubic-framework sodium cobalt-based metaphosphate NaCo(PO) was recently demonstrated to be an attractive Na cationic conductor. It can be potentially used in the next-generation rechargeable Na ion batteries. The crystal structure and electrical conductivity were studied and found to have a three-dimensional framework with interconnecting tunnels for Na migration ( J.

In-situ deposition of sodium titanate thin film as anode for sodium-ion micro-batteries developed by pulsed laser deposition.

Sodium-ion thin-film micro-batteries form a niche sector of energy storage devices. Sodium titanate, NaTiO (NTO) thin films were deposited by pulsed laser deposition (PLD) using solid-state synthesized polycrystalline NaTiO compound. The phase-purity and crystallinity of NTO in bulk and thin-film forms were confirmed by Rietveld refinement.