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Li metal batteries (LMBs) with high energy density electrodes have emerged as the primary candidate for next-generation batteries owing to its superiority over conventional Li-ion technology. However, the safe operation of these systems under thermal abuse conditions remains primary concern regardless of the tremendous efforts to prevent short circuits through dendrite formation. In this context, we employ differential scanning calorimetry technique to investigate the thermal stability of Li-S and Li-NMC532 metal batteries. The calorimetric measurements identify separator melting together with anode-centric thermal degradation reactions as the primary mechanism of thermal runaway. Separator with poor thermal stability (low melting point), could instigate an internal short circuit that leads to exponential temperature rise due to the rapid release of electrical energy. An in-house physics-based modeling technique utilizes the knowledge of thermal stability at the materials level to predict the thermal safety of LMBs for pouch cell configuration. Simulations reveal that the thermal stability of the separator and parasitic reactions at the anode (Li metal) dictate the critical onset temperature of thermal runaway in Li metal batteries. The severity of thermal runaway can be modulated by carefully designing (capacity loading ratio (N/P)) the thickness of metal anode and advanced separator with better thermal stability. [ABSTRACT FROM AUTHOR]

Mn 3 O 4 thick film electrodes have been synthesized by spray pyrolysis method. Effect of its two important synthesis parameters viz. solution feed rate and substrate temperature has been studied. Solution feed rate was studied in the range of 150 to 250 cc.min −1 while substrate temperature was varied from 325 to 400 °C. X-ray diffraction studies confirms Hausmannite crystal structure and SEM studies show spherical grains, uniformly distributed porous microstructure obtained for deposited Mn 3 O 4 thick films. The contact angle measurements show these electrodes have very low contact angle in the range of 2−8° and high surface energy. Cyclic voltammetry study showed specific and interfacial capacitance of Mn 3 O 4 electrodes increased with increase in solution feed rate, due to increased thickness of films. On the other hand, substrate temperature shows effect on film morphology, grain size and porosity, however, does not show any explicit effect on specific and interfacial capacitance. Highest values of specific and interfacial capacitance exhibited by Mn 3 O 4 are 187.79 F.g −1 and 0.82 F.cm −2 respectively for sample prepared at 250 cc.min −1 solution feed rate and 325 °C substrate temperature. The calculated energy density and power density for the same sample was 26.08 Wh.kg −1 and 1.01 kW.kg −1 respectively. [ABSTRACT FROM AUTHOR]

Abstract: High energy density Li-ion hybrid electrochemical capacitors (Li-HEC) are fabricated with 3 D architectured high surface area porous carbon (HSPC) derived from the poly(acrylamide-co-acrylic acid) potassium salt in a single step without any activating agent. The obtained HSPC exhibits high specific surface area of 1490 m2 g−1 and characterized with several analytical techniques. Li-HEC is fabricated with insertion type Li4Ti5O12 anode by adjusting the mass balance based on the single electrode performance with Li. The Li-HEC delivered the maximum energy density of ∼55 Wh kg−1, which is much higher than commercially available activated carbon (∼36 Wh kg−1). Further HSPC based Li-HEC delivered excellent cycleability and rendered ∼87% of initial value after 2000 cycles. [Copyright &y& Elsevier]

All solid‐state batteries are desirable for a range of energy storage applications which require high energy density. Achieving a high energy density in a solid‐state battery requires the operation of an energy dense anode with a composite solid‐state cathode. Pores and/or voids within a solid state cathode are ion‐blocking and thus control over the concentration and distribution of pores in the initial electrode and cycled electrode is desirable. This study provides an understanding of the interplay between electrode microstructure and mechanics on active material utilization in solid state cathodes composed of NCM 811 and Li6PS5Cl. Decreasing the solid electrolyte particle size leads to greater active material‐electrolyte contact and less total deformation when exposed to an external load. Composite cathodes with greater compliance can potentially decrease strain between the active material and solid electrolyte, decrease delamination events and result in higher overall active material utilization and high capacity retention. [ABSTRACT FROM AUTHOR]

Covalent organic framework (COF) can grow into self-exfoliated nanosheets. Their graphene/graphite resembling microtexture and nanostructure suits electrochemical applications. Here, covalent organic nanosheets (CON) with nanopores lined with triazole and phloroglucinol units, neither of which binds lithium strongly, and its potential as an anode in Li-ion battery are presented. Their fibrous texture enables facile amalgamation as a coin-cell anode, which exhibits exceptionally high specific capacity of ≈720 mA h g-1 (@100 mA g-1). Its capacity is retained even after 1000 cycles. Increasing the current density from 100 mA g-1 to 1 A g-1 causes the specific capacity to drop only by 20%, which is the lowest among all high-performing anodic COFs. The majority of the lithium insertion follows an ultrafast diffusion-controlled intercalation (diffusion coefficient, DLi+ = 5.48 × 10-11 cm2 s-1). The absence of strong Liframework bonds in the density functional theory (DFT) optimized structure supports this reversible intercalation. The discrete monomer of the CON shows a specific capacity of only 140 mA h g-1 @50 mA g-1 and no sign of lithium intercalation reveals the crucial role played by the polymeric structure of the CON in this intercalation-assisted conductivity. The potentials mapped using DFT suggest a substantial electronic driving-force for the lithium intercalation. The findings underscore the potential of the designer CON as anode material for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Covalent organic framework (COF) can grow into self‐exfoliated nanosheets. Their graphene/graphite resembling microtexture and nanostructure suits electrochemical applications. Here, covalent organic nanosheets (CON) with nanopores lined with triazole and phloroglucinol units, neither of which binds lithium strongly, and its potential as an anode in Li‐ion battery are presented. Their fibrous texture enables facile amalgamation as a coin‐cell anode, which exhibits exceptionally high specific capacity of ≈720 mA h g−1 (@100 mA g−1). Its capacity is retained even after 1000 cycles. Increasing the current density from 100 mA g−1 to 1 A g−1 causes the specific capacity to drop only by 20%, which is the lowest among all high‐performing anodic COFs. The majority of the lithium insertion follows an ultrafast diffusion‐controlled intercalation (diffusion coefficient, DLi+ = 5.48 × 10−11 cm2 s−1). The absence of strong Li‐framework bonds in the density functional theory (DFT) optimized structure supports this reversible intercalation. The discrete monomer of the CON shows a specific capacity of only 140 mA h g−1 @50 mA g−1 and no sign of lithium intercalation reveals the crucial role played by the polymeric structure of the CON in this intercalation‐assisted conductivity. The potentials mapped using DFT suggest a substantial electronic driving‐force for the lithium intercalation. The findings underscore the potential of the designer CON as anode material for Li‐ion batteries. [ABSTRACT FROM AUTHOR]

• Temperature controlled route ideal electro-catalytic credentials. • Binder free union between the current collector and electro-catalyst. • The morphology and composition controlled kinetics. • Overpotential 71 mV and 126 mV for cathodic currents of 10 mAcm−2 and 100 mAcm−2. We propose coupling of hydrothermal-synthesis with the high-temperature phosphorisation step for the direct growth of optimized morphology (nanoneedle arrays) and composition (NiP 2 /CoP 2) of NiCo-phosphide (NCP) on carbon fiber paper. Cathodic H 2 evolution (HER) depicts the morphology and composition-dependent kinetics. The electrocatalysts prepared at phosphorisation temperatures of 300 °C (NCP-300), 400 °C(NCP-300), and 500 °C(NCP-300) depicted the overpotentials of 96 mV, 71 mV, and 80 mV respectively for the generation of cathodic current equivalent to10 mAcm−2. The overpotentials required for generation of 100mAcm−2 are 155 mV, 126 mV and 185 mV for NCP-300, NCP-400 and NCP-500 respectively. [ABSTRACT FROM AUTHOR]