Papers by srikanth mateti
Applied Materials Today, Dec 1, 2022
ACS Applied Materials & Interfaces
Additive Manufacturing
Abstract Additive manufacturing, also known as 3D printing, overcomes many design and manufacturi... more Abstract Additive manufacturing, also known as 3D printing, overcomes many design and manufacturing constraints to allow almost direct production of metals into complicated geometries. However, coarse columnar grain structures, up to the millimeter-scale, are commonly produced in titanium and its alloys through the layer-by-layer process and this causes significant anisotropy in mechanical properties. Here we report an innovative approach for microstructure refinement of an additively manufactured Ti-6Al-4V alloy via directed energy deposition of boron nitride nanotube (BNNT) decorated powders. With only 0.4 wt% BNNT, this process results in unprecedented grain refinement down to a few micrometers and over 50% strength enhancement. A unique texture-weakened structure comprising fine equiaxed grains is achieved via a novel nanoparticle-mediated nucleation mechanism enabled by local hypereutectic precipitation in the rapid solidification process. This mechanism is highly suited to the metallurgical environment of metal additive manufacturing and creates a pathway for screening effective grain refiners in titanium and other alloy systems.
SSRN Electronic Journal, 2022
Materials Today Physics, 2021
Microporous and Mesoporous Materials, 2021
Abstract Materials with well-defined porous structures, high conductivity and surface area are pr... more Abstract Materials with well-defined porous structures, high conductivity and surface area are promising candidates in energy storage, oil absorption and catalysis applications. This work demonstrates, for the very first time, a new facile route to prepare carbon fibers exhibiting hierarchical porous designs that mimic deep-sea sponges. The fibres were prepared via wet spinning method using poly (acrylonitrile)-block-poly (methyl methacrylate) (ANMMA) block copolymers. The hierarchical porous morphologies were formed in carbon fibers due to the combined effect of self-assembly and solvent/non-solvent induced phase separation during the coagulation process. Continuous and interconnected macroporous features were observed in fibers with abundant small-sized nanopores and the fiber surface area was calculated to be 499 m2/g. Electrochemical analyses showed that the fibers possess a specific capacitance of 130 F/g at 10 A/g with excellent cyclic stability of 97% capacitance retention after 10,000 cycles. The porous fibers also exhibited excellent sorption properties with a range of organic solvents and oil, demonstrating high absorbent potential for oil/chemical clean-up. The absorption capacities were in the range of 70–92 g/g for different types of organic solvents and oil. This study paves the way towards a new class of porous carbon materials with nature mimicking designs for multifunctional applications.
Chemical Communications, 2021
Controlling mechanochemistry by varying milling conditions.
ACS Nano, 2020
Flexible and high-performance batteries are urgently required for powering flexible/wearable elec... more Flexible and high-performance batteries are urgently required for powering flexible/wearable electronics. Lithium-sulfur batteries with a very high energy density are a promising candidate for high-energy-density flexible power source. Here, we report flexible lithium-sulfur full cells consisting of ultrastable lithium cloth anodes, polysulfone-functionalized separators, and free-standing sulfur/graphene/boron nitride nanosheet cathodes. The carbon cloth decorated with lithiophilic three-dimensional MnO2 nanosheets not only provides the lithium anodes with an excellent flexibility but also limits the growth of the lithium dendrites during cycling, as revealed by theoretical calculations. Commercial separators are functionalized with polysulfone (PSU) via a phase inversion strategy, resulting in an improved thermal stability and smaller pore size. Due to the synergistic effect of the PSU-functionalized separators and boron nitride-graphene interlayers, the shuttle of the polysulfides is significantly inhibited. Because of successful control of the shuttle effect and dendrite formation, the flexible lithium-sulfur full cells exhibit excellent mechanical flexibility and outstanding electrochemical performance, which shows a superlong lifetime of 800 cycles in the folded state and a high areal capacity of 5.13 mAh cm-2. We envision that the flexible strategy presented herein holds promise as a versatile and scalable platform for large-scale development of high-performance flexible batteries.
Journal of Power Sources, 2020
There is an increasing demand for boron nitride nanosheets (BNNSs) for a range of applications su... more There is an increasing demand for boron nitride nanosheets (BNNSs) for a range of applications such as advanced composite materials, ion/gas selective membranes, and energy storage. These applications require stable, high-concentration BNNS dispersions as a precursor, which is a challenge because BNNSs do not disperse easily. We report a simple, yet efficient, mechanochemical exfoliation technique to prepare functionalized BNNSs with excellent dispersibility in water and organic solvents. The resultant amino-modified BNNSs (BNNS-NH2) are stable in ethanol for 3 months at an unprecedented high concentration of 46 ± 2 mg/mL. We provide insights into the dispersibility mechanism for amino- and hydroxyl-functionalized BNNSs. High-concentration BNNS dispersions enable a facile painting method that can coat a uniform, insulating, and antioxidant BNNS layer on arbitrary surfaces. In addition, different functional groups enhance the selectivity of different ions of the functionalized BNNS membranes for water purification and other ion separation applications. These stable, high-concentration BNNS dispersions make many exciting applications possible.
Materials Today, 2021
Abstract Atomically thin boron nitride nanosheets (BNNSs) are normally considered to be chemicall... more Abstract Atomically thin boron nitride nanosheets (BNNSs) are normally considered to be chemically inert, which makes them difficult to be functionalized. Many applications require new surface functionalities. Significant efforts have been made towards surface engineering and assembly of BNNSs. In this article, we contribute a critical review of the topic on challenges and solutions in surface engineering and assembly of BNNSs. We first outline the mechanistic insights of tunable surface functionalization of BNNSs, and then highlight some new breakthroughs, seminal studies, and trends in the area that have been most recently reported by our groups and others. Recent application researches include but are not limited to: (1) chemical catalysis; (2) biocompatible BN functional nanomaterials for biological and biomedical applications; (3) molecularly engineered BN surfaces for sensing and drug delivery applications; and (4) the construction of thermally conductive and electrically insulating composites. There is also an in-depth discussion on the merits of the processing-structure–property relationships in the functionalized BNNSs. Finally, with this review article, we hope to spark new ideas and inspire new functionalization strategies by fundamentally understanding surface properties and engineering BNNSs with programmable structures and predictable properties.
Electrochimica Acta, 2021
Abstract First-principles calculations forecast that germanium incorporated graphite has potentia... more Abstract First-principles calculations forecast that germanium incorporated graphite has potential to be used as high performance negative electrode for lithium-ion batteries due to large mobility of electrons at the heterointerface. Inspired by this first-principles calculations, a novel functional structure of thin graphite nanoplatelets embedding a finely dispersed germanium component is fabricated through a scalable ball milling technique for the first time. Nitrogen adsorption-desorption isotherms and electron microscopy investigation demonstrate that the obtained electrode materials exhibit mesoporous features where germanium nanoparticles are implanted into the graphitic matrix of thin flakes. Such a novel structure provides several advantages including large surface area, high accessibility of lithium ions and shortened lithium ion diffusion distances, which enable fast ion and electron transfer at the interface of electrolyte and electrode. As results, the obtained electrode demonstrates promising electrochemical performance with a charge capacity of 822 mAh g−1 after 200 cycles at 0.1 C, high rate capacity of 325 mAh g−1 at 10 C and good cyclic stability with a capacity retention of 97%. This work delivers a robust electrode design strategy as well as the most practical route for the improvement of germanium-based anodes for application in lithium-ion batteries.
Journal of Power Sources, 2021
Abstract Free-standing thin film electrodes hold huge promise for solid-state and micro batteries... more Abstract Free-standing thin film electrodes hold huge promise for solid-state and micro batteries required by a range of portable electronic devices. However, for lithium-sulfur (Li–S) and lithium-metal polysulfide (Li-MSx; M = Mo, V, Ti, etc.) batteries, the promising thin film electrodes are not possible yet because of low melting point of sulfur. Here, for the first time, we have developed amorphous molybdenum sulfide (MoSx) – carbon (Cy) composite thin-films using a magnetron sputtering method with novel co-deposition of molybdenum metal and sulfur-carbon composite. The thin films were used as the free-standing cathode for Li-MSx cells that demonstrates excellent cycling performance and rate capability without any shuttle effect. The Li-MoSx cells exhibit a high areal-capacity of 115 μAh/cm2 at the current density of 20 μA/cm2, an excellent stability of 500 cycles and remarkable rate capability with no traces of shuttle effect. Density functional theory (DFT)-Molecular dynamics (MD) based calculations reveal the insertion of lithium via an optimal mix of conversion and intercalation reactions without breaking the base Mo-Sx structure, eliminating the shuttle effect, and producing stable cycling performance.
Advanced Energy and Sustainability Research, 2021
RSC Advances, 2020
A solvent-free, low-cost, high-yield and scalable single-step ball milling process is developed t... more A solvent-free, low-cost, high-yield and scalable single-step ball milling process is developed to construct 2D MoS2/graphene hybrid electrodes for lithium-ion batteries.
Journal of Nanoscience and Technology, 2018
Advanced Functional Materials, 2020
Ion gel electrolytes show great potential in solid‐state batteries attributed to their outstandin... more Ion gel electrolytes show great potential in solid‐state batteries attributed to their outstanding characteristics. However, because of the strong ionic nature of ionic liquids, ion gel electrolytes generally exhibit low lithium‐ion transference number, limiting its practical application. Amine‐functionalized boron nitride (BN) nanosheets (AFBNNSs) are used as an additive into ion gel electrolytes for improving their ion transport properties. The AFBNNSs‐ion gel shows much improved mechanical strength and thermal stability. The lithium‐ion transference number is increased from 0.12 to 0.23 due to AFBNNS addition. More importantly, for the first time, nuclear magnetic resonance analysis reveals that the amine groups on the BN nanosheets have strong interaction with the bis(trifluoromethanesulfonyl)imide anions, which significantly reduces the anion mobility and consequently increases lithium‐ion mobility. Battery cells using the optimized AFBNNSs‐ion gel electrolyte exhibit stable lithium deposition and excellent electrochemical performance. A LiFePO4|Li cell retains 92.2% of its initial specific capacity after the 60th cycle while the cell without AFBNNSs‐gel electrolyte only retains 53.5%. The results not only demonstrate a new strategy to improve lithium‐ion transference number in ionic liquid electrolytes, but also open up a potential avenue to achieve solid‐state lithium metal batteries with improved performance.
Batteries & Supercaps, 2020
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Papers by srikanth mateti