Engineering topics

Lin, Liang

Publications and source records attributed to Lin, Liang.

4 records

DOE OSTI2024

Lattice and Local Electronic Structure Modulation Enables Ultra-Long-Life Li-Rich Cathode Materials

Effectively alleviating severe performance deterioration including rapid capacity decay and continuous voltage fading of Li-rich layered oxide (LLO) cathodes by suppressing the irreversible oxygen release and transition metal (TM) migration is a critical challenge during prolonged cycling. Herein, we report a Sb-doped LLO (SLLO) cathode with shortened TM oct –TM oct distance and modulated local electronic structure, which can significantly enhance the oxygen vacancy formation energy and TM migration energy barriers. Therefore, the SLLO cathode showcases an impressive energy density of 1052 Wh kg –1 at 0.2 C and an outstanding rate capability of 214 mAh g –1 at 5 C with a remarkable capacity retention of 79.2% even after 1000 cycles. It should be pointed out that it exhibits greatly enhanced voltage stability with an outstanding voltage retention of 86.2% after cycling 1600 times at 10 C. In conclusion, this work provides a prototype for significantly enhancing the reversibility in electrochemical reactions of high-capacity layered cathode materials.

25 ENERGY STORAGE↗

DOE OSTI2024

Design principles of heterointerfacial redox chemistry for highly reversible lithium metal anode

High electrochemical reversibility is required for the application of high-energy-density lithium (Li) metal batteries; however, inactive Li formation and SEI (solid electrolyte interface)-instability-induced electrolyte consumption cause low Coulombic efficiency (CE). The prior interfacial chemical designs in terms of alloying kinetics have been used to enhance the CE of Li metal anode; however, the role of its redox chemistry at heterointerfaces remains a mystery. Herein, the relationship between heterointerfacial redox chemistry and electrochemical transformation reversibility is investigated. It is demonstrated that the lower redox potential at heterointerface contributes to higher CE, and this enhancement in CE is primarily due to the regulation of redox chemistry to Li deposition behavior rather than the formation of SEI films. Low oxidation potential facilitates the formation of the surface with the highly electrochemical binding feature after Li stripping, and low reduction potential can maintain binding ability well during subsequent Li plating, both of which homogenize Li deposition and thus optimize CE. In particular, Mg hetero-metal with ultra-low redox potential enables Li metal anode with significantly improved CE (99.6%) and stable cycle life for 700 cycles at 3.0 mA cm -2 . This work provides insight into the heterointerfacial design principle of next-generation negative electrodes for highly reversible metal batteries.

25 ENERGY STORAGE↗

DOE OSTI2023

On fast simulation of dynamical system with neural vector enhanced numerical solver

The large-scale simulation of dynamical systems is critical in numerous scientific and engineering disciplines. However, traditional numerical solvers are limited by the choice of step sizes when estimating integration, resulting in a trade-off between accuracy and computational efficiency. To address this challenge, we introduce a deep learning-based corrector called Neural Vector (NeurVec), which can compensate for integration errors and enable larger time step sizes in simulations. Our extensive experiments on a variety of complex dynamical system benchmarks demonstrate that NeurVec exhibits remarkable generalization capability on a continuous phase space, even when trained using limited and discrete data. NeurVec significantly accelerates traditional solvers, achieving speeds tens to hundreds of times faster while maintaining high levels of accuracy and stability. Moreover, NeurVec’s simple-yet-effective design, combined with its ease of implementation, has the potential to establish a new paradigm for fast-solving differential equations based on deep learning.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2023

Lattice Oxygen Redox Reversibility Modulation in Enhancing the Cycling Stability of Li-Rich Cathode Materials

The practical application of lithium-rich layered oxides is prohibited by the drawbacks such as severe capacity and voltage degradation resulting from unstable oxygen redox environment and the accompanied irreversible oxygen release. In this report a facile and effective strategy is proposed to regulate the oxygen redox chemistry via foreign Fe doping and its induced intrinsic transition metal (TM) doping as well as the in situ constructed spinel surface layer. The Fe doping, together with the induced intrinsic TM dual doping, can stabilize the lattice oxygen in the bulk due to the formed stronger Fe—O bond, and restrain the irreversible TM migration and then the undesirable phase transformation. More importantly, thermodynamical energy barrier of oxygen activation is dramatically decreased by the O 2p–Fe 3d charge-transfer, allowing stable oxygen redox activity. And the pre-constructed spinel layer can effectively stabilize the surface lattice oxygen and suppress harmful interfacial side-reactions. Such a simple optimizing method make the modified cathode exhibit a high specific capacity of 298 mAh g -1 at 0.2 C, outstanding cycling stability with a superior capacity and voltage retentions of 92.5% and 90.8%, respectively, after 400 cycles at 1 C. This study provides a new direction for developing advanced Li-ion batteries.

25 ENERGY STORAGE↗