Education & Certifications
M.S., Stanford University, Mechanical Engineering (2018)
B.S., Peking University, Theoretical and Applied Mechanics (2016)
- Neural network approach to response surface development for reaction model optimization and uncertainty minimization COMBUSTION AND FLAME 2023; 251
High-Performance Lithium-Sulfur Batteries via Molecular Complexation.
Journal of the American Chemical Society
Beyond lithium-ion technologies, lithium-sulfur batteries stand out because of their multielectron redox reactions and high theoretical specific energy (2500 Wh kg-1). However, the intrinsic irreversible transformation of soluble lithium polysulfides to solid short-chain sulfur species (Li2S2 and Li2S) and the associated large volume change of electrode materials significantly impair the long-term stability of the battery. Here we present a liquid sulfur electrode consisting of lithium thiophosphate complexes dissolved in organic solvents that enable the bonding and storage of discharge reaction products without precipitation. Insights garnered from coupled spectroscopic and density functional theory studies guide the complex molecular design, complexation mechanism, and associated electrochemical reaction mechanism. With the novel complexes as cathode materials, high specific capacity (1425 mAh g-1 at 0.2 C) and excellent cycling stability (80% retention after 400 cycles at 0.5 C) are achieved at room temperature. Moreover, the highly reversible all-liquid electrochemical conversion enables excellent low-temperature battery operability (>400 mAh g-1 at -40 °C and >200 mAh g-1 at -60 °C). This work opens new avenues to design and tailor the sulfur electrode for enhanced electrochemical performance across a wide operating temperature range.
View details for DOI 10.1021/jacs.3c05209
View details for PubMedID 37589666
Stable sodium-sulfur electrochemistry enabled by phosphorus-based complexation.
Proceedings of the National Academy of Sciences of the United States of America
2021; 118 (49)
A series of sodium phosphorothioate complexes are shown to have electrochemical properties attractive for sodium-sulfur battery applications across a wide operating temperature range. As cathode materials, they resolve a long-standing issue of cyclic liquid-solid phase transition that causes sluggish reaction kinetics and poor cycling stability in conventional, room-temperature sodium-sulfur batteries. The cathode chemistry yields 80% cyclic retention after 400 cycles at room temperature and a superior low-temperature performance down to -60°C. Coupled experimental characterization and density functional theory calculations revealed the complex structures and electrochemical reaction mechanisms. The desirable electrochemical properties are attributed to the ability of the complexes to prevent the formation of solid precipitates over a fairly wide range of voltage.
View details for DOI 10.1073/pnas.2116184118
View details for PubMedID 34857631
A new strategy of characterizing hydrocarbon fuels using FTIR spectra and generalized linear model with grouped-Lasso regularization
View details for DOI 10.1016/j.fuel.2020.119419