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Kumta, Prashant N.

Publications and source records attributed to Kumta, Prashant N..

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Electrospinning of PVdF-HFP: novel composite polymer electrolytes (CPES) with enhanced ionic conductivities for lithium-sulfur batteries

The invention relates to lithium ion batteries and, more particularly, to lithium ion conducting composite polymer electrolyte separators. The separators include a nanofiber mat composed of electrospun nanofibers. The nanofibers include a polymer having one or more polar halogen groups, a lithium-containing solid or liquid electrolyte and nanoparticle filler. The polymer, electrolyte and filler are combined to form a solution that is subjected to the electro-spinning process to produce electrospun nanofibers in the form of the mat.

Kumta, Prashant N.↗
DOE OSTI2023

Cathodes and electrolytes for rechargeable magnesium batteries and methods of manufacture

The invention relates to Chevrel-phase materials and methods of preparing these materials utilizing a precursor approach. The Chevrel-phase materials are useful in assembling electrodes, e.g., cathodes, for use in electrochemical cells, such as rechargeable batteries. The Chevrel-phase materials have a general formula of Mo 6 Z 8 (Z=sulfur) or Mo 6 Z 1 8-yZ 2 y (Z 1 =sulfur; Z 2 =selenium), and partially cuprated Cu 1 Mo 6 S 8 as well as partially de-cuprated Cu 1-x Mg x Mo 6 S 8 and the precursors have a general formula of M x Mo 6 Z 8 or M x Mo 6 Z 1 8-yZ 2 y , M=Cu. The cathode containing the Chevrel-phase material in accordance with the invention can be combined with a magnesium-containing anode and an electrolyte.

Kumta, Prashant N.↗
DOE OSTI2023

High capacity, air-stable, structurally isomorphous lithium alloy multilayer porous foams

The invention relates to composite multilayer lithium ion battery anodes that include a porous metal alloy foam, and a lithium ion conductor coating applied to the metal alloy foam. The metal alloy foam can include structurally isomorphous alloys of lithium and, optionally, lithium and magnesium. The lithium ion conductor coating can include ternary lithium silicate, such as, lithium orthosilicate. Lithium ions from the ternary lithium silicate may be deposited within the pores of the metal alloy foam. Optionally, the lithium ion conductor coating may include a dopant. The dopant can include one or more of magnesium, calcium, vanadium, niobium and fluorine, and mixtures and combinations thereof.

Kumta, Prashant N.↗
DOE OSTI2022

Electrochemically Stable High Energy Density Lithium-Sulfur Batteries

Lithium-Sulfur batteries (LSB) have emerged as one of the strong contenders for high energy density rechargeable batteries in the Li-ion battery domain. The LSB system is considered as the most promising to achieve the next milestone in energy density of 500 Wh/kg. However, the LSB system is plagued with problems of polysulfide formation which are soluble in the organic electrolyte leading to loss in capacity and eventual cell failure. The problem is further compounded by dendrite formation on the Li anode during electrochemical cycling leading to puncturing of the separator causing eventual short-circuiting of the cell and consequent heat generation resulting in major safety hazards of flammability of the organic liquid electrolyte and impending explosion. This chapter describes various approaches developed to combat both cathode and anode issues. These involve synthesis and characterization of complex framework materials (CFMs) for confining the polysulfides and sulfur in the LSB cathodes. The CFMs include a CFM host and a coating applied to the CFM host, which includes one or more form of an electronic conductor, a lithium-ion conductor and a functional electrocatalyst for electrocatalytically converting the soluble polysulfides to Li 2 S. Further, sulfur is infiltrated into the CFM host creating a sulfur-carbon linkage serving as effective anchors for trapping the ensuing polysulfides. The systems have been tested in coin cells and pouch cells with metallic Li anodes under lean electrolyte conditions of 3-4 μl/mg of electrolyte (E) to sulfur (S) ratios showing promise and feasibility. New emergent dendrite-free alloys have also been identified to test against pure Li and CFM cathodes in coin cell and pouch cell configurations under lean electrolyte conditions. Results of these studies are described and discussed with thoughts on future directions.

25 ENERGY STORAGE↗
DOE OSTI2022

Non-noble metal based electro-catalyst compositions for proton exchange membrane based water electrolysis and methods of making

The invention provides electro-catalyst compositions for an anode electrode of an acid mediated proton exchange membrane-based water electrolysis system. The compositions include a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof, and a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, cooper oxide, zirconium oxide, nickel oxide and mixtures thereof. Further, the non-noble metal component can include a dopant. The dopant can be at least one element selected from Groups III, V, VI and VII of the Periodic Table. The compositions can be prepared using any solution based methods involving a surfactant approach or a sol gel approach. Further, the compositions are prepared using noble metal and non-noble metal precursors. Furthermore, a thin film containing the compositions can be deposited onto a substrate to form the anode electrode.

Kumta, Prashant N.↗
DOE OSTI2020

Cathodes and electrolytes for rechargeable magnesium batteries and methods of manufacture

The invention relates to Chevrel-phase materials and methods of preparing these materials utilizing a precursor approach. The Chevrel-phase materials are useful in assembling electrodes, e.g., cathodes, for use in electrochemical cells, such as rechargeable batteries. The Chevrel-phase materials have a general formula of Mo6Z8 and the precursors have a general formula of MxMo6Z8. The cathode containing the Chevrel-phase material in accordance with the invention can be combined with a magnesium-containing anode and an electrolyte.

Kumta, Prashant N.↗
DOE OSTI2020

Constitutional under-potential plating (CUP) – New insights for predicting the morphological stability of deposited lithium anodes in lithium metal batteries

Lithium (Li) cycling in lithium metal batteries (LMBs) inevitably witnesses a non-planar Li/electrolyte interface (cellular/dendritic microstructure) affecting the performance, safety and reliability of LMBs. Herein, the “constitutional under-potential plating” (CUP) concept is presented for the first time to understand the evolution, formation and predict the morphological stability/instability of the Li/electrolyte interface. Here, the CUP condition, a measure of the driving force for interface perturbation, occurs when the true potential gradient at the interface is smaller than the equilibrium electrodeposition potential gradient at the Li/electrolyte interface resulting in the electrolyte ahead of the Li-electrolyte interface to be in an under-potential state. Detailed CUP criterion calculations conducted herein establishes the relationship of battery operating conditions (e.g. current density, potential gradient) with the electrolyte properties (e.g. Li-ion transference number and diffusion coefficient) predicting the morphological stability condition at the interface. In addition to the driving force for interface perturbation, the capillarity effect or the Gibbs Thomson effect, a measure of the resistance to perturbation of the perturbed interface is discussed for understanding the influence of interfacial energy/adhesion energy between the current collector and the deposited Li on the overall morphological stability of the Li/electrolyte interface, a critical criterion for the unwanted dendritic morphology.

25 ENERGY STORAGE↗
NASA NTRS2004

LiCoO2 and SnO2 Thin Film Electrodes for Lithium-Ion Battery Applications

There is an increasing need for small dimension, ultra-lightweight, portable power supplies due to the miniaturization of consumer electronic devices. Rechargeable thin film lithium-ion batteries have the potential to fulfill the growing demands for micro-energy storage devices. However, rechargeable battery technology and fabrication processes have not kept paced with the advances made in device technology. Economical fabrication methods lending excellent microstructural and compositional control in the thin film battery electrodes have yet to be fully developed. In this study, spin coating has been used to demonstrate the flexibility of the approach to produce both anode (SnO2) and cathode (LiCoO2) thin films. Results on the microstructure crystal structure and electrochemical properties of the thin film electrodes are described and discussed.

Maranchi, Jeffrey P.↗