Yi Cui

Bio: Yi Cui is an academic researcher from Stanford University. The author has contributed to research in topics: Anode & Lithium. The author has an hindex of 220, co-authored 1015 publications receiving 199725 citations. Previous affiliations of Yi Cui include KAIST & University of California, Berkeley.

Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

Abstract: Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Here, we demonstrate physical and mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high-performance Li-ion batteries.

High-capacity Li2S–graphene oxide composite cathodes with stable cycling performance

Abstract: With its high theoretical capacity of 1166 mA h g−1, Li2S is a promising prelithiated cathode material for applications such as vehicle electrification and grid energy storage. Herein, we demonstrate facile synthesis of Li2S–graphene oxide composites for use as high-capacity and stable-cycling Li2S cathodes. The wrapping of graphene oxide onto the surface of Li2S through favorable lithium–oxygen interactions helps to minimize the dissolution of intermediate polysulfides into the electrolyte during cycling, which is a major reason for rapid capacity decay. Using the Li2S–graphene oxide composites as a cathode material, we demonstrate a high discharge capacity of 782 mA h g−1 of Li2S (∼1122 mA h g−1 of S) with stable cycling performance over 150 charge–discharge cycles.

A Replacement Reaction Enabled Interdigitated Metal/Solid Electrolyte Architecture for Battery Cycling at 20 mA cm–2 and 20 mAh cm–2

Abstract: Metal anodes represent as a prime choice for the coming generation rechargeable batteries with high energy density. However, daunting challenges including electrode volume variation and inevitable side reactions preclude them from becoming a viable technology. Here, a facile replacement reaction was employed to fabricate a three-dimensional (3D) interdigitated metal/solid electrolyte composite electrode, which not only provides a stable host structure for buffering the volume change within the composite but also prevents side reactions by avoiding the direct contact between active metal and liquid electrolyte. As a proof-of-concept demonstration, a 3D interdigitated zinc (Zn) metal/solid electrolyte architecture was fabricated via a galvanic replacement reaction between Zn metal foil and indium (In) chloride solution followed by electrochemical activation, featuring the interdigitation between metallic Zn and amorphous indium hydroxide sulfate (IHS) with high Zn2+ conductivity (56.9 ± 1.8 mS cm-1), large Zn2+ transference number (0.55), and high electronic resistivity [(2.08 ± 0.01) × 103 Ω cm]. The as-designed Zn/IHS electrode sustained stable electrochemical Zn plating/stripping over 700 cycles with a record-low overpotential of 8 mV at 1 mA cm-2 and 0.5 mAh cm-2. More impressively, it displayed cycle-stable performance with low overpotential of 10 mV under ultrahigh current density and areal capacity (20 mA cm-2, 20 mAh cm-2), which outperformed all the reported Zn metal electrodes in mild aqueous electrolyte. The fabrication of interdigitated metal/solid electrolyte was generalized to other metal pairs, including Zn/Sn and Zn/Co, which provide inspiration for next-generation Zn metal batteries with high energy density and reversibility.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。