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Cheng, Gang

Publications and source records attributed to Cheng, Gang.

At least 19 records
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DOE OSTI2025

Novel Zwitterionic Polyurethane-in-Salt Electrolytes with High Ion Conductivity, Elasticity, and Adhesion for High-Performance Solid-State Lithium Metal Batteries

This study presents a novel polymer-in-salt (PIS) zwitterionic polyurethane-based solid polymer electrolyte (zPU-SPE) that offers high ionic conductivity, strong interaction with electrodes, and excellent mechanical and electrochemical stabilities, making it promising for high-performance all solid-state lithium batteries (ASSLBs). The zPU-SPE exhibits remarkable lithium-ion (Li+) conductivity (3.7 × 10⁻⁴ S cm−1 at 25 °C), enabled by exceptionally high salt loading of up to 90 wt.% (12.6 molar ratio of Li salt to polymer unit) without phase separation. It addresses the limitations of conventional SPEs by combining high ionic conductivity with a Li+ transference number of 0.44, achieved through the incorporation of zwitterionic groups that enhance ion dissociation and transport. The high surface energy (338.4 J m−2) and elasticity ensure excellent adhesion to Li anodes, reducing interfacial resistance and ensuring uniform Li+ flux. When tested in Li||zPU||LiFePO₄ and Li||zPU||S/C cells, the zPU-SPE demonstrated remarkable cycling stability, retaining 76% capacity after 2000 cycles with the LiFePO4 cathode, and achieving 84% capacity retention after 300 cycles with the S/C cathode. Molecular simulations and a range of experimental characterizations confirm the superior structural organization of the zPU matrix, contributing to its outstanding electrochemical performance. The findings strongly suggest that zPU-SPE is a promising candidate for next-generation ASSLBs.

Wang, Kun↗
DOE OSTI2023

Triboelectric nanogenerator for harvesting energy from water

An apparatus including a first member including a first electrode, a second member coupled to the first member about an axis, including a second electrode, and a surface layer between the first electrode and the second electrode, the second member is rotatable with respect to the axis by an energy flow to change triboelectric charges on the electrodes, and to affect a flow of electrons between the electrodes. A self-powered sensor for detecting a chemical including a generator having an electrode, and a superhydrophobic surface layer for receiving an energy flow carrying triboelectric charges, the surface layer includes a TiO 2 layer with nanostructures, and a power indicator indicative of whether the chemical is present based on power output of the triboelectric generator, the energy flow is a solution flow, the solution comprising the chemical and water, and the chemical removes at least one triboelectric charge from the water.

Wang, Zhong Lin↗
DOE OSTI2022

Determination of the Structures of Lignin Subunits and Nanoparticles in Solution by Small‐Angle Neutron Scattering: Towards Improving Lignin Valorization

Abstract Lignin nanoparticles (LNPs) are usually produced from lignin solution through supersaturation. The structure of the lignin in solution is still poorly understood due to structural variability of isolated lignins. Here, lignins were extracted from different plants to establish a general pattern of their structure in several lignin solvents. Lignin molecules (lignin subunits) and larger aggregates were observed in dimethyl sulfoxide (DMSO), ethylene glycol (EG) and 0.1 N NaOD solutions by small‐angle neutron scattering (SANS). It was proposed that the aggregates were composed of lignin subunits with a higher molecular weight and a higher ratio of the aliphatic to phenolic hydroxyl groups. The size, shape, and compactness are important factors that affect the uses of the LNPs, which were obtained from the SANS data for the first time. A discrepancy in the radius between SANS and DLS was discovered, pointing to a large hydration shell around the LNPs in aqueous solutions. The cytotoxicity of the corncob lignin, kraft lignin, and their LNPs were measured and compared.

Zhang, Xin↗
DOE OSTI2022

Composite Solid Ion Conductor with Engineered Lithium Interface

Successful widespread commercialization of electric vehicles is contingent upon development of safe high energy density batteries capable of long cycle life. Lithium metal affords the highest theoretical capacity (3,860 mAh/g) and lowest electrochemical potential (-3.04V vs SHE), which offers the highest specific energy density of anode materials today. While Li-ion batteries are capable of delivering energy densities of 400-600 Wh/kg, the development of lithium metal batteries such as Li-S and Li-air may boost this number up to 650 and 950 Wh/kg, respectively. However, significant progress towards the passivation of lithium metal must occur before the energy density benefit can be realized. Issues with lithium dendrite formation, anode volume expansion, and continuous solid electrolyte interphase (SEI) build-up often result in significant safety concerns, high cell resistance, and poor cycle life. The intrinsic high reactivity between lithium metal with conventional lithium ion electrolytes (organic carbonate-based solvents) makes it extremely difficult to overcome these problems. In this project, Wildcat performed focused, fundamental research and development on composite polymer/ceramic electrolytes and protected lithium metal anodes to develop an all solid state lithium metal battery targeting the DOE requirements to enable commercialization. Wildcat successfully leveraged its high throughput battery platform and explored a broad composite electrolyte compositional space. Additionally, Wildcat screened large numbers of inorganic and organic coatings for lithium metal protection using in situ liquid methods and translated the best results to all solid cells. The proposed composite polymer/ceramic electrolyte and a protected lithium metal anode enabled a solid-state lithium metal battery. The ultimate targets from this effort will deliver a safe all solid-state lithium metal pouch cell with over 350 Wh/kg and over 1,000 cycles (C/3) with the cost estimate below $100/kWh. During the course of the project, we demonstrated stable cycling of 10’s of cycles with the composite SSE and our protected lithium. The work has continued after the conclusion of the DOE funding, demonstrating further improvements in catholyte composition and thinner composite solid electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2022

Recent advances in biological activities of lignin and emerging biomedical applications: A short review

As an abundant biopolymer, lignin gains interest owing to its renewable nature and polyphenolic structure. It possesses many biological activities such as antioxidant activity, antimicrobial activity, and biocompatibility. Studies are being carried out to relate the biological activities to the polyphenolic structures. These traits present lignin as a natural compound being used in biomedical field. Lignin nanoparticles (LNPs) are being investigated for safe use in drug and gene delivery, and lignin-based hydrogels are being explored as wound dressing materials, in tissue engineering and 3D printing. In addition, lignin and its derivatives have shown the potential to treat diabetic disease. This review summarizes latest research results on the biological activities of lignin and highlights potential applications exampled by selective studies. It helps to transform lignin from a waste material into valuable materials and products.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Electrolyte formulations for electrochemical cells containing a silicon electrode

Additives to electrolytes that enable the formation of comparatively more robust SEI films on silicon anodes. The SEI films in these embodiments are seen to be more robust in part because the batteries containing these materials have higher coulombic efficiency and longer cycle life than comparable batteries without such additives.

Zhu, Ye↗
DOE OSTI2021

Highly Concentrated Electrolytes: Electrochemical and Physicochemical Characteristics of LiPF 6 in Propylene Carbonate Solutions

Highly concentrated electrolytes (HCEs) based on LiPF 6 in propylene carbonate (PC) have been examined as lithium-ion battery electrolytes. These HCEs have lower ionic conductivities and higher viscosities than ethylene carbonate (EC) electrolytes with 1.2 M LiPF 6 , but they have higher Li + ion transference numbers. Electrochemical cycling behaviour of LiNi 0.8 Co 0.015 Al 0.05 O 2 //graphite cells with 3.2 M LiPF 6 in PC resembles that of cells with EC-based electrolytes; the HCE cells have higher impedance, which can be lowered by increasing test temperature. By employing Raman and infrared spectroscopy, combined with density functional theory and ab initio molecular dynamics simulations, we reveal that the Li + solvation structure and speciation are key factors that determine cell performance. Two distinct regimes are observed as a function of salt concentration—in the conventional regime, the solvation number (SN) is mostly constant, while in the HCE regime it decreases linearly. Graphite exfoliation is suppressed only at very high salt concentrations ( > 2.4 M), where [ PC ] free /[Li + ] < 1 and P F 6 − f r e e > P C f r e e . Results from the Advanced Electrolyte Model indicate that Li + desolvation improves at higher LiPF 6 concentrations, thereby mitigating PC co-intercalation into the graphite. However, Li + ion transport is hindered in the HCEs, which increases impedance at both the oxide-positive and graphite-negative electrodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Electrolyte formulations for electrochemical cells containing a silicon electrode

Additives to electrolytes that enable the formation of comparatively more robust SEI films on silicon anodes. The SEI films in these embodiments are seen to be more robust in part because the batteries containing these materials have higher coulombic efficiency and longer cycle life than comparable batteries without such additives. The additives preferably contain a nitrate group.

25 ENERGY STORAGE↗
DOE OSTI2020

Electrolyte formulations for electrochemical cells containing a silicon electrode

Additives to electrolytes that enable the formation of comparatively more robust SEI films on silicon anodes. The SEI films in these embodiments are seen to be more robust in part because the batteries containing these materials have higher coulombic efficiency and longer cycle life than comparable batteries without such additives.

25 ENERGY STORAGE↗
DOE OSTI2019

Triboelectric nanogenerator for harvesting energy from water

A generator for harvesting energy from flowing water is disclosed. The generator harvests electrostatic energy as well as mechanical kinetic energy from the flowing water. In one aspect, the generator includes a plurality of blades arranged in a radially outward fashion. Each blade includes an electrode and a surface layer for receiving flowing water carrying triboelectric charges. The flowing water affects a flow of electrons between the electrode and ground. In another aspect, the generator includes a first member with a first electrode, and a second member coupled to the first member about an axis. The second member includes a second electrode, and a surface layer between the first electrode and the second electrode. The second member is rotatable with respect to the axis to change triboelectric charges on the electrodes, and to affect a flow of electrons between the electrodes.

Wang, Zhong Lin↗
DOE OSTI2019

Robust triboelectric nanogenerator based on rolling electrification

A generator for converting mechanical energy or hydropower or wind energy into electrical energy is disclosed. The generator includes a first member and a second member in contact with the first member to generate triboelectric charges. The second member rolls against the first member to generate a flow of electrons between two electrodes. Another embodiment of the generator includes two electrodes, and a member in contact with the two electrodes to generate triboelectric charges. The member rolls against the electrodes to generate a flow of electrons between the two electrodes.

Wang, Zhong Lin↗
DOE OSTI2019

Electrolyte formulations for electrochemical cells containing a silicon electrode

Additives to electrolytes that enable the formation of comparatively more robust SEI films on silicon anodes. The SEI films in these embodiments are seen to be more robust in part because the batteries containing these materials have higher coulombic efficiency and longer cycle life than comparable batteries without such additives. The additives preferably contain a dicarbonate group or are an organo-metallic hydride.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Magnetic Properties of (Pr{sub 1−x}Sm{sub x}){sub 2}Fe{sub 14}B Melt-Spun Ribbons

The magnetic properties of (Pr{sub 1−x}Sm{sub x}){sub 2}Fe{sub 14}B melt-spun ribbons with varying x from 0 to 1.0 have been studied. The optimum magnetic property of Pr{sub 2}Fe{sub 14}B ribbon could be obtained with the surface velocity of copper wheel of 30 m/s. By melt spinning method, the formation of α-Fe impurity phase in the (Pr{sub 1−x}Sm{sub x}){sub 2}Fe{sub 14}B samples could be inhibited, and the grain could be aligned. Sm element could be incorporated into Pr{sub 2}Fe{sub 14}B main crystalline phase and formed (Pr,Sm){sub 2}Fe{sub 14}B phase with space group P4{sub 2}/mnm. The Curie temperature (T{sub c}) of the (Pr{sub 1−x}Sm{sub x}){sub 2}Fe{sub 14}B ribbons increases gradually from 555 to 617 K with the increase of Sm content x. Both the coercivity (H{sub c}) and remanence ratio (M{sub r}/M{sub s}) decrease firstly and then increase with the Sm content increasing. As long as the Sm content x does not exceed 0.1, the squareness of demagnetization curve remains good. The critical value of transition from easy c-axis to easy plane for (Pr{sub 1−x}Sm{sub x}){sub 2}Fe{sub 14}B ribbons is x= 0.6. When the Sm content x is up to 0.6, all the H{sub c} and M{sub r}/M{sub s} achieved the minimum value, i.e., 243 Oe and 0.346, respectively.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Electrolyte formulations for electrochemical cells containing a silicon electrode

Additives to electrolytes that enable the formation of comparatively more robust SEI films on silicon anodes. The SEI films in these embodiments are seen to be more robust in part because the batteries containing these materials have higher coulombic efficiency and longer cycle life than comparable batteries without such additives. The additives preferably contain a nitrate group.

25 ENERGY STORAGE↗