Shivaraju Guddehalli Chandrappa

Sb–In alloying suppresses lithiation-induced volume changes and enhances Li-ion transport. The optimized Sb _0.5 In _0.5 anode exhibits durable cycling, excellent rate capability, and wide-temperature lithium-storage performance.

Highlights General classification and methodology guidelines to halide-based solid electrolytes for high-voltage all-solid-state batteries. A comprehensive evaluation of synthesis and interfacial modification methods that direct the enhancement of ionic conductivity and electrochemical stability. Potential uses of halide-based solid electrolytes in full-cell configurations with cathodes based on high voltage in Li-ion batteries and beyond-Li-ion systems, such as Li–S, Li–O₂, and Na-ion batteries.

The unstable solid‐electrolyte interface (SEI) poses a major obstacle to the widespread use of rechargeable magnesium batteries (RMBs) as high‐volumetric‐capacity next‐generation energy storage systems. This issue is effectively mitigated by adding 3 wt.% tris(trimethylsilyl) borate (TMSB, C9H27BO3Si3) to a state‐of‐the‐art Cl‐free magnesium tetrakis(hexafluoroisopropyloxy)borate in dimethoxyethane (Mg[B(hfip) ₄ ] ₂ /DME) non‐aqueous electrolyte. The modified electrolyte enables stable Mg||Mo ₆ S ₈ (Chevrel phase, CP) full cell operation for up to 1000 cycles at a 1C rate. Tip‐enhanced Raman spectroscopy (TERS) reveals that TMSB scavenges degraded electrolyte components and facilitates the formation of a uniform and thin SEI on the magnesium anode. Reflection anisotropy spectroscopy (RAS) further demonstrates that TMSB transforms the interfacial structure, creating a more isotropic and robust SEI during the initial stripping and plating process, thereby extending electrochemical cycling stability. This approach presents a compelling pathway for practical RMB development by stabilizing the SEI and optimizing magnesium electrolyte formulations.

The development of non‐aqueous lithium‐oxygen (Li‐O ₂ ) batteries is hindered by inefficient discharge product decomposition, side reactions with the electrolyte, and high charge overpotentials (>1 V). This study explores the use of sodium cobalt borate (Na ₃ CoB ₅ O ₁₀ , NCBO) with cobalt in tetrahedral geometry as an oxygen electrocatalyst for non‐aqueous Li‐O ₂ batteries. The prepared cobalt borate exhibits an oxygen evolution reaction (OER) overpotential of 326 mV _RHE at a current density of 10 mA cm ⁻² and a Tafel slope of 42 mV dec ⁻¹ in 1 m KOH. Density Functional Theory (DFT) calculations identify the OH‐covered (101) surface of NCBO as the preferred OER site, with an overpotential between 451 and 544 mV. In Li‐O ₂ batteries, the NCBO cathode demonstrates 200 cycles with an overpotential of 1.95 V and 56.00% round‐trip efficiency at a capacity limit of 500 mA h g ⁻¹ , along with a smaller charge overpotential of 0.64 V at a capacity limit of 2000 mA h g ⁻¹ . Post‐cycling analysis of NCBO electrodes reveals electronically conductive Lithium Superoxide (LiO ₂ ) as the dominant discharge product. As revealed by DFT studies, the promising performance of NCBO in Li‐O ₂ batteries is attributed to its tetrahedral Co coordination, highlighting its potential for electrocatalytic applications.

High energy density rechargeable Li−O₂ batteries (LOBs) have garnered significant attention as a promising energy storage device. However, the sluggish oxygen redox kinetics impeded the efficiency and cycling performance during both the charge and discharge processes. To address this issue, we introduce a non‐noble‐trimetallic MnCo_2‐xCu_xO₄ (X=0 to 1) spinel interface as a bifunctional catalyst, to improve the reaction kinetics and cycle stability of LOBs. The half‐filled e_g orbital improves the synergistic interaction between Cu⁺/Cu²⁺, Co²⁺/Co³⁺, and Mn³⁺/Mn⁴⁺ redox pairs in the lattice, which enhances catalytic performance. In the series of MnCo_2‐xCu_xO₄ (X=0 to 1) spinel catalyst MnCo_1.75Cu_0.25O₄ (MCU25) emerged as a standout performer. This exhibited notable half‐cell performance, featuring superior ORR/OER bifunctional electrocatalytic activity with a ΔE of 1.15 V (vs RHE). Notably, the MCU25 cathode exhibited remarkable stability for over 1250 hours, enduring 225 cycles at 500 mA h g⁻¹ and stable up to 70 cycles at a capacity limit of 1000 mA h g⁻¹ in LOBs. Furthermore, it demonstrated an exceptional discharge‐specific capacity of 11272 mA h g⁻¹ at a current density of 175 mA g⁻¹, exceeding the performance achieved by state‐of‐the‐art RuO₂ around 10180 mA h g⁻¹.

Lithium-ion batteries (LIBs) serve as the backbone of modern technologies with ongoing efforts to enhance their performance and sustainability driving the exploration of new electrode materials. This study introduces a new type of alloy-conversion-based gallium ferrite (GFO: GaFeO₃) as a potential anode material for Li-ion battery applications. The GFO was synthesized by a one-step mechanochemistry-assisted solid-state method. The powder X-ray diffraction analysis confirms the presence of an orthorhombic phase with the Pc2₁ n space group. The photoelectron spectroscopy studies reveal the presence of Ga³⁺ and Fe³⁺ oxidation states of gallium and iron atoms in the GFO structure. The GFO was evaluated as an anode material for Li-ion battery applications, displaying a high discharge capacity of ∼887 mA h g^-1 and retaining a stable capacity of ∼200 mA h g^-1 over 450 cycles, with a Coulombic efficiency of 99.6 % at a current density of 100 mA g^-1. Cyclic voltammetry studies confirm an alloy-conversion-based reaction mechanism in the GFO anode. Furthermore, density functional theory studies reveal the reaction mechanism during cycling and Li-ion diffusion pathways in the GFO anode. These results strongly suggest that the GFO could be an alternative anode material in LIBs.

Chloride–ion batteries (CIBs) offer a compelling alternative to conventional battery systems, particularly in applications demanding cost‐effectiveness and resource sustainability. However, the development of tailored electrode materials remains a critical bottleneck for CIB advancement. In this study, an untapped class of perovskite‐based material, potassium hexachlorostannate (K₂SnCl₆, denoted as KSC) is synthesized via a facile mechanochemical route for the first time. The prepared KSC is subjected to various characterization techniques to confirm its crystal structure and morphology. Herein, KSC exhibits intriguing electrochemical performance in a non‐aqueous CIB configuration, utilizing a lithium metal counter electrode. Furthermore, ex situ X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS) analysis, reveal a conversion reaction mechanism involving chloride ion shuttling and provide insights into structural evolution during cycling. Moreover, the density functional theory (DFT) studies support additional degradation products that can potentially limit the performance of these materials as potential battery electrodes in CIBs.

Chloride ion batteries (CIBs) offer a compelling alternative to lithium-ion systems, particularly in applications demanding cost-effectiveness and resource sustainability. However, the development of tailored electrode materials remains a critical bottleneck for CIB advancement. In this study, we synthesized an untapped class of perovskite-based material potassium hexachlorostannate (K2SnCl6, denoted as KSC) via a facile mechanochemical route for the first time. The prepared KSC was subjected to various characterization techniques to confirm its crystal structure and morphology. Herein, KSC exhibited intriguing electrochemical performance in a non-aqueous CIB configuration, utilizing a lithium metal counter electrode. Furthermore, ex-situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis, reveal a conversion reaction mechanism involving chloride ion shuttling and provide insights into structural evolution during cycling. Moreover, the Density functional theory (DFT) studies supported additional degradation products that could potentially limit the performance of these materials, limiting the performance of these materials as potential battery electrodes in CIBs.

In this work, a structurally revivable, chloride‐ion conducting solid electrolyte (SE), CsSn_0.9In_0.067Cl₃, with a high ionic conductivity of 3.45 × 10⁻⁴ S cm⁻¹ at 25 °C is investigated. The impedance spectroscopy, density functional theory, solid‐state ³⁵Cl NMR, and electron paramagnetic resonance studies collectively reveal that the high Cl⁻ ionic mobility originates in the flexibility of the structural building blocks, Sn/InCl₆ octahedra. The vacancy‐dominated Cl⁻ ion diffusion encompasses co‐ordinated Sn/In(Cl) site displacements that depend on the exact stoichiometry, and are accompanied by changes in the local magnetic moments. Owing to these promising properties, the suitability of the CsSn_0.9In_0.067Cl₃, as an electrolyte is demonstrated by designing all‐solid‐state batteries, with different anodes and cathodes. The comparative investigation of interphases with Li, Li–In, Mg, and Ca anodes reveals different levels of reactivity and interphase formation. The CsSn_0.9In_0.067Cl₃ demonstrates an excellent humidity tolerance (up to 50% relative humidity) in ambient air, maintaining high structural integrity without compromises in ionic conductivity, which stands in contrast to commercial halide‐based lithium conductors. The discovery of a halide perovskite conductor, with air processability and structure revival ability paves the way for the development of advanced air processable SEs, for next‐generation batteries.

The rechargeable zinc–air battery is a clean technology for energy storage applications but is impeded by the slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during its cycling. Herein, a series of lanthanum cobaltate based perovskites are synthesised with the B-site cation deficiencies in the structure occupied by Ru substitution: LaCo_1−xRu_xO_3−δ (x = 0, 0.1, 0.2, 0.3 and 0.5). These compositions were designed to enhance the OER/ORR activities, which are two vital reactions for rechargeable Zn–air batteries. Powder X-ray diffraction analysis revealed that increasing the Ru substitution >20% (x > 0.2) alters the LaCoO₃ crystal structure from rhombohedral to orthorhombic. Photoelectron spectroscopy studies reveal that the surface oxygen vacancies increased in the Ru substituted catalyst, a property important for enhancing the OER/ORR efficiency. The LaCo_0.8Ru_0.2O_3−δ (LCRO82) catalyst exhibits promising electrocatalytic activities in both the OER and the ORR in 0.1 M KOH solution. Furthermore, the LCRO82 catalyst was evaluated as a cathode for rechargeable Zn–air battery applications displaying a high power density of 136 mW cm⁻² at a current density of 175 mA cm⁻² and a stable charge–discharge voltage gap of 0.78 V after 1440 cycles, with excellent cycling stability over 240 h.