Engineering topics

Xing, Yangchuan

Publications and source records attributed to Xing, Yangchuan.

9 records

DOE OSTI2022

A Flame Spray Process for Cathode Materials Manufacturing for Lithium Ion Batteries

Flame (combustion) processes are the most economic ones to produce fine powders and have been used to produce pigment titanium oxide and fused silica in large volumes. In this work a flame spray pyrolysis (FSP) process has been developed to make metal oxide powders for the positive electrode materials at low cost. In particular, the work was focused on making metal oxides of NMC materials with stoichiometric compositions and desired morphologies. Our FSP is a green chemical process employing low cost biomass precursors for the battery material manufacturing. The detailed results of the synthesis, characterization, and battery testing of the NMC powder materials will be presented.

25 ENERGY STORAGE↗

DOE OSTI2022

Nanostructured Powders Made from Flame Spray Pyrolysis for Li-Ion Cathode

Flame processes are the most economic ones to produce fine powders and have been used to produce pigment titanium oxide and fused silica in large volumes. In this work a flame spray pyrolysis (FSP) process is used to make positive electrode materials for Li-ion battery, which is made of complex metal oxide powders, such as Li(Ni1/3Mn1/3Co1/3)O2. In particular, the work was focused on making the NMC materials with stoichiometric compositions and desired morphologies. During the pyrolysis process different morphologies can be formed, involving often powders with primary nanoparticles. Such nanostructures were found to have affected the battery performance. Detailed results of the synthesis, characterization, and battery testing of the NMC powder materials will be presented.

25 ENERGY STORAGE↗

DOE OSTI2022

Transition Metal Oxide Powders Made from Flame Spray Pyrolysis for Li-Ion Batteries

In 2012 the U.S. Department of Energy introduced its EV Everywhere Grand Challenge, with a stated goal of enabling “plug-in electric vehicles (PEVs) that are as affordable and convenient for the American family as gasoline-powered vehicles by 2022.” This requires a reduction in battery costs from the current $500/kWh to around $125/kWh. Most approaches have been to eliminate vehicle weight through lightweighting and to improve the energy density of battery materials. But what if we were able to just make the materials cheaper instead? To this end we introduce a green, low-cost method of producing cathode materials using an integrated flame spray pyrolysis process.

25 ENERGY STORAGE↗

DOE OSTI2022

Hydrogenated and Carbon-coated Na2Ti6O13 Nanowires as High-Rate Anode Materials for Lithium Ion Batteries

The main disadvantage for sodium titanate as an anode material for LIBs is its low electronic conductivity, resulting in poor rate capability. Several approaches have been taken in an attempt to improve the electronic conductivity of sodium/lithium titanate, such as electronic material coating/mixing, ionic doping, comminution, etc.; but as of yet there has been no uniform carbon coating reported on sodium titanate for LIBs. In this work, we detail a facile technique to create uniform thin carbon coating layers on Na2Ti6O13 nanowires (NTO-C). In addition, we also explored self-doped Ti3+ on carbon coated Na2Ti6O13 nanowires (H-NTO-C) in an effort to further improve its electronic conductivity. The detailed results of the synthesis, characterization, and electrochemical performance of the NTO-based materials (NTO, NTO-C and H-NTO-C) will be presented.

25 ENERGY STORAGE↗

DOE OSTI2022

Renewable Solvents to Replace Water in the Synthesis of Battery Materials

Our lab has been engaged in using glycerol to replace water in the synthesis of metal oxides, especially those for use in Li-ion battery. Glycerol is a byproduct from biodiesel production. The U.S. biodiesel manufacturers generate about 1 billion pounds of glycerol yearly, which needs to be utilized for producing value added products. By using glycerol as a solvent, we found that it can replace water to prepare many metal oxide powders. The materials synthesis processes have the potential to significantly reduce manufacturing cost and alleviate the environmental issues with aqueous processes. In this talk, I will present some of our work in materials synthesis using glycerol as a solvent. In particular, I will introduce the work on making active cathode materials for the Li-ion battery.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Lithium Ion Cathode Materials Prepared Using Glycerol as Solvent and Reactant

Two different types of cathode materials were prepared using glycerol as a solvent and reactant. The LiMn1/3Ni1/3Co1/3O2 layered oxide cathode material was successfully synthesized with a shorter time of heat treatment of 8hr at 900°C. An appreciated capacity retention of 83.7% after 100 cycles with an initial discharge capacity of 177.1 mAh/g at 0.1C (discharge rate) has been achieved. Another cathode material with the formula of Li1.2 Mn0.51Ni0.145+xCo0.145-xO2 (x=0 (LR2), 0.0725 (LR1)), as a Li-rich cathode material, has been also successfully synthesized using glycerol. It was shown that LR1 discharge capacity was increased from 185 to 213 mAh/g after 20 cycles and ended up with 194.9 mAh/g after 60 cycles at 0.1C (discharge rate). This material shows an exceptional discharge capacity retention, lower toxic cobalt component, and lower production cost comparing with other Li-rich cathode materials. Detailed results of powder material synthesis, characterization, and battery testing will be presented to demonstrate that glycerol as a green solvent in the synthesis of battery materials.

25 ENERGY STORAGE↗

DOE OSTI2022

Economic Analysis of Battery (NMC) Cathode Material Production in Flame Spray Process with Sustainable Solvents

To reduce the cathode material manufacturing cost, our lab has developed a flame spray process that utilize sustainable solvent glycerol as solvent to manufacture the cathode material. The economic analysis of the new green chemical process was studied based on discounted cash flow method. The major economic indicator used in this study is the minimum cathode material selling price (MCSP), whereas the co-precipitation method for NMC333 production was selected as the reference for economic analysis.

25 ENERGY STORAGE↗

DOE OSTI2022

An Integrated Flame Spray Process for Low Cost Production of Battery Materials for Lithium Ion Batteries and Beyond

The overall objective of this project was to develop an advanced manufacturing technology for Li-ion battery materials production at low cost and in a green chemical process using glycerol as solvent to replace water. It was aimed at developing a prototype pilot production line to reduce production cost by at least 25% to the baseline. During the course of this project, research was conducted to understand spray drying and combustion of eutectic solvent precursors of glycerol and metal salts (acetates) in the formation of mixed metal oxide powders. Reactor design and optimization were done to facilitate spray drying and combustion in powder formation and processing. Various cathode materials powders were produced, including lithium nickel-cobalt-manganese oxide (NCM) and lithium nickel-cobalt-aluminum oxide (NCA). These cathode materials powders were tested in half coin cells for their performances, with materials performances of 160 mAh/g for NCM111 and 200 mAh/g for NCA. NCA powders were also produced using a slurry spray-drying process and tested in full pouch cells. A pilot scale flame assisted spray drying reactor was constructed and demonstrated for its production rate exceeding the target of production rate of four metric tons per year. The work performed in this project has been documented in 9 peer reviewed journal publications, 8 conference presentations, and two IP disclosures/patent applications.

25 ENERGY STORAGE↗

DOE OSTI2022

Weak magnetic field-dependent photoluminescence properties of lead bromide perovskites

The strong spin–orbit coupling (SOC) in lead halide perovskites, when inversion symmetry is lifted, has provided opportunities for investigating the Rashba effect in these systems. Moreover, the strong orbital moment, which, in turn, impacts the spin-pair in singlet and triplet electronic states, plays a significant role in enhancing the optoelectronic properties in the presence of external magnetic fields in lead halide perovskites. Here, we investigate the effect of weak magnetic fields (<1 T) on the photoluminescence (PL) properties of CsPbBr 3 nanocrystals with and without Ruddlesden–Popper (RP) faults and single crystals of CH 3 NH 3 PbBr 3 . Along with an enhancement in the PL intensity as a function of an external magnetic field, which is observed in both lead bromide perovskites, the PL emission red-shifts in CsPbBr 3 nanocrystals. Density-functional theory calculations of the electronic band-edge in CsPbBr 3 show almost no change in the energy gap as a function of the external magnetic field. The experimental results, thus, suggest the role of mixing of the triplet and singlet excitonic states under weak magnetic fields. This is further deduced from an enhancement in PL lifetimes as a function of the field in CsPbBr 3 ⁠. In CH 3 NH 3 PbBr 3⁠ , an increase in PL intensity is observed under weak magnetic fields; however, no changes in the peak energy or PL lifetimes are observed. The internal magnetic fields due to SOC are characterized for all three samples and found to be the highest for CsPbBr 3 nanocrystals with RP faults.

36 MATERIALS SCIENCE↗