Researchers Reveal Novel Thermal Conduction Crossover due to Broken Parity in Superlattice

A research team from Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a crossover of thermal conduction with a third-order-like singularity in a Fermi-Pasta-Ulam-Tsingou (FPUT) superlattice. The research results were published in Physical Review E in May 2025.

Parity represents the mirror inversion symmetry in physics. Commonly, interaction parity between atoms is broken in a crystalline solid due to the asymmetric interatomic repulsion. Symmetry breaking often involves a phase transition, however, it is still unclear if there are any comparable behaviors in a crystalline solid due to the broken interaction parity.Motivated by such a challenge, a research team led by Prof. CHEN Jige at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a crossover of thermal conduction with a third-order-like singularity in a Fermi-Pasta-Ulam-Tsingou (FPUT) superlattice.The research results were published in Physical Review E in May 2025.The superlattice is consisted of repeating periodic cells of arithmetically increased cubic nonlinearity. Researchers find that, before a critical point of interaction asymmetry, thermal conduction is cell-length-independent. After crossing the critical point, thermal conduction relies on the unit cell length.The calculation of reflection symmetry and configuration entropy of the atomic displacement reveals a third-order-like singularity at the critical point, which further determines the peculiar dynamics of energy carriers.The result indicates a high-order singularity arising from the broken interaction parity in a crystalline solid and a promising strategy in adjusting phononic superlattice materials. It enlightens our understanding of the critical role of interatomic interaction parity in lattice thermal behaviors since thermal expansion is the most common feature in a crystalline solid.Schematic of the FPUT Superlattice and its complete Hamiltonian. (Image by SARI)

Researchers Unveiled Key Role of Bridge Adsorbed Hydrogen in Efficient Acidic Hydrogen Production

A research team at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences designed a face-centered cubic-Ru nanocrystal modified with Pt atomic chains and unveiled the important role of *Hbridge intermediates adsorbed on Pt-Ru atomic pairs in determining the intrinsic activity of HER.

Proton exchange membrane water electrolysis (PEMWE) has emerged as a promising approach in green hydrogen production, owing to its broad power fluctuation adaptability, rapid dynamic response, and high energy efficiency under elevated current densities, which enable effective integration of intermittent renewable energy sources such as wind and solar power.For hydrogen evolution reaction (HER) in acid, atop and multiple adsorbed hydrogen are key intermediates on Pt-group metal. However, the role of bridge hydrogen intermediate (*Hbridge) is oftenneglectedin experiments.Motivated by this challenge, a research team led by Prof. YANG Hui at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences designed a face-centered cubic-Ru nanocrystal modified with Pt atomic chains and unveiled the important role of *Hbridge intermediates adsorbed on Pt-Ru atomic pairs in determining the intrinsic activity of HER.The research results were published in Advanced Materials.The results of in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy and density functional theory calculations, demonstrate the key role of *Hbridge in enhancing HER catalytic activity and stability. The electrons leap from Pt-Ru pair site to *Hbridge significantly accelerates the Tafel kinetics.For the HER performances evaluation, the developed Pt-Ru(fcc) achieves an ultralow overpotential of ~ 4 mV at a current density of 10 mA cm−2 under 2.0 μgPt cm-2in three-electrode configuration, and the intrinsic activity at 50 mV is 10.6 times higher than that of commercial Pt/C.The PEMWE device integrated by advanced fcc electrocatalyst with ultra-low Pt loadings of only 10 μg cm-2, which is 30 ~ 50 folds lower than that used in current industrial PEMWE systems (300~500 μg cm-2), achieves exceptional activity (1.0 A cm-2 at 1.61 V) and remarkable stability (4.0 μV h-1 degradation rate over 1000 h at 1.0 A cm-2). The PEMWE based 80 μm Gore membrane under identical operating conditions requires only 1.54 and 1.58 V to achieve 1.0 and 1.5 A cm-2. Furthermore, the device exhibits negligible decay during the 240 h fluctuating tests.The identification of the key role of *Hbridge provides mechanistic insights into the activity origin of the Pt–Ru bimetallic catalysts, and opens new avenues for designing next-generation bimetallic catalysts for clean hydrogen energy.Table of Contents (Image by SARI)In situ ATR-SEIRAS of hydrogen intermediate (Image by SARI)The performance of PEMWE (Image by SARI)<!--!doctype-->

Researchers Propose Bit-Cigma: A Zero-Error, Sparsity-Aware Matrix Multiplication Accelerator for AI

A research group from Shanghai Advanced Research Institute of Chinese Academy of Sciences has unveiled Bit-Cigma, a revolutionary generic matric multiplication accelerator hardware architecture that optimizes bit-sparsity, ensures zero-error accuracy, and remodels floating-point computations. The results were published in Feb 2025 in IEEE Transactions on Computers.

Recently, a research group led by Prof. ZHU Yongxin from Shanghai Advanced Research Institute of Chinese Academy of Sciences has unveiled Bit-Cigma, a revolutionary generic matric multiplication accelerator hardware architecture that optimizes bit-sparsity, ensures zero-error accuracy, and remodels floating-point computations.The results were published in Feb 2025 in IEEE Transactions on Computers, a top-tier journal in the field of computer architecture.Matrix multiplication underpins artificial intelligence (AI) and scientific computing, driving processes such as neural network training and complex simulations. These fields demand efficient computing power capable of both floating-point (FP) and quantized integer (QINT) operations with exceptional performance and accuracy.However, the development of efficient matrix multiplication accelerators faces two persistent challenges. First, the inherent bit-level redundancy in binary data representation wastes computational resources and limits computational efficiency. Second, the floating-point exponent matching relies on slow, resource-heavy methods that bottleneck throughput and compromise accuracy.Bit-Cigma is a scalable, bit-level sparsity-aware architecture designed to handle various datatypes while delivering superior performance, accuracy, and efficiency for matrix multiplications across diverse tasks. The researchers proposed the Compact Canonical Signed Digit (CCSD) encoding technique, a streamlined on-chip method that slashes redundant computations by maximizing bit-level sparsity, all at half the cost of traditional approaches. For large matrices, the team devised a segmented approach that splits data into manageable blocks and aligns floating-point exponents dynamically. This ensures pinpoint accuracy and boosts processing speed and throughput without taxing hardware resources.Extensive experiments demonstrate that Bit-Cigma, utilizing CCSD, achieves a performance boost of 3 to 4 times and improves efficiency by over 10 times compared to state-of-the-art FP and QINT accelerators. Additionally, Bit-Cigma achieves zero computational error, a feat not matched by other accelerators.The Bit-Cigma architecture and the CCSD technique pave the way for more efficient, high-performance solutions for generic matrix multiplication. These advancements promise to support a range of applications and set the foundation for future hardware-centric high-performance systems.

Researchers Developed a Novel Ni Hollow Fiber Electrode for High-efficiency CO2 Electroreduction

In a study published in The Innovation​, a research team from Shanghai Advanced Research Institute of the Chinese Academy of Sciences constructed a hierarchical SnO2(101)@Ni composite hollow-fiber penetration electrode (HPE), which helped to realize high-efficiency CO2 electroreduction to formate in neutral electrolyte at ampere-level.

In a study published in The Innovation, Prof. WEI Wei, Prof. CHEN Wei and Prof. SONG Yanfang from Shanghai Advanced Research Institute of the Chinese Academy of Sciences constructed a hierarchical SnO2(101)@Ni composite hollow-fiber penetration electrode (HPE), which helped to realize high-efficiency CO2 electroreduction to formate in neutral electrolyte at ampere-level.The electrochemical CO2 reduction reaction (eCO2RR), powered by renewable energy, is a promising method for converting CO2 into value-added products, thereby enabling sustainable carbon-neutral cycles. However, the practical implementation of eCO2RR technology is challenged by limitations in activity, selectivity, and stability.To simultaneously achieve high formate Faradaic efficiency, high current density, and long-term stability, researchers constructed facet-oriented SnO2 nanoflowers arrayed on the exterior of three-dimensional nickel hollow fibers by a facile hydrothermal method.This electrode demonstrates exceptional electrocatalytic performance for converting CO2 to formate. A formate selectivity of 94% and stability of 300 h with a current density of 1.3 A cm-2 at −1.1 V (vs. RHE) are attained under ambient conditions. Notably, an extremely high CO2 single-pass conversion rate of 85% is achieved, outperforming prominent catalysts reported in electrocatalysis.The synergetic combination of the unique nanostructures and their advanced spatial configuration is proposed to be responsible for the facet-oriented SnO2 with a hierarchical structure, providing fully exposed active sites and facilitating mass and charge transfers. Enhanced mass transfer in the hollow fiber electrode verified by electrochemical measurements and well-retained Sn4+ species confirmed by in situ spectroscopy synergistically boost the high CO2 conversion activity. In situ spectroscopy and theoretical calculation results demonstrate that the SnO2(101) facet favors *OCHO intermediate formation and *HCOOH desorption, leading to high formate selectivity.This study provides a straightforward approach to the precise fabrication of composite hollow fiber electrodes, enabling highly efficient electrocatalytic reactions with gas molecules.Schematic diagram of electroreduction of CO2 to formate over SnO2@Ni hollow fiber penetration electrode (Image by SARI)

Researchers Propose a Novel Hollow Fiber Electrode for Efficient Electrocatalytic Conversion of CO2

In a study published in Angewandte Chemie, Prof. WEI Wei, Prof. CHEN Wei and Prof. SONG Yanfang from Shanghai Advanced Research Institute of the Chinese Academy of Sciences constructed a hierarchical Cl-SnO2@Ni HF Composite hollow-fiber penetration electrode (HPE), which helped to realize high-efficiency CO2 electroreduction to formate in neutral electrolyte at ampere-level.Renewable energy-driven electrochemical CO2 reduction has emerged as a promising technology for a sustainable future. However, achieving efficient production of storable liquid fuels at ampere-level current densities remains a significant hurdle in the large-scale implementation of CO2 electroreduction.To further improve the selectivity and conversion rate of formate at ampere-level current density, researchers constructed chlorine-doped SnO2 nanoflowers arrayed on the exterior of three-dimensional nickel hollow fibers by a facile hydrothermal method.This electrode demonstrates exceptional electrocatalytic performance for converting CO2 to formate, achieving a remarkable formate selectivity of 99% and a CO2 single-pass conversion rate of 93% at 2 A cm-2. Furthermore, it exhibits excellent stability, maintaining a formate selectivity of above 94% for 520 h at a current density of 3 A cm-2.Experimental results combined with theoretical calculations confirm that the enhanced mass transfer facilitated by the hollow fiber penetration effect, coupled with the well-retained Sn4+ species and Sn-Cl bonds, synergistically elevates the activity of CO2 conversion. The incorporation of chlorine into SnO2 enhances electron transport and CO2 adsorption, substantially lowering the reaction energy barrier for the crucial intermediate *OCHO formation, and boosting the formate production.This work provides valuable insights into the rational design of high-performance catalytic electrodes for CO2 electroreduction.Schematic diagram of electroreduction of CO2 to formate over Cl-SnO2@Ni HF penetration electrode. (Image by SARI)

​Researchers Propose Multifunctional Buffer Layer Engineering for Efficient and Stable Wide-Bandgap Perovskite

In a study published in Angewandte Chemie, a research team from Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, collaborated with City University of Hong Kong reported a facile and effective strategy for precisely modulating the perovskite by incorporating AlOx deposited by atomic layer deposition (ALD) on the top interface.

Perovskite solar cells (PSCs) have become a revolutionary photovoltaic technology because of their high performance, low cost, and easy fabrication of large-scale flexible devices. However, the solution processing and the low formation energy of perovskites lead to numerous defects formed at both the bulk and interfaces of the perovskite layer, which ultimately results in a substantial deficit in the open-circuit voltage (VOC).In a study published in Angewandte Chemie, Prof. LU Linfeng from Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, collaborated with Prof. Alex K.-Y. Jen at City University of Hong Kong reported a facile and effective strategy for precisely modulating the perovskite by incorporating AlOx deposited by atomic layer deposition (ALD) on the top interface.Researchers found that Al3+ ions not only infiltrated in the perovskite layer but also interacted with halide ions. The modification contributed to realizing better-matched energy levels, suppressed ion migration and minimized interfacial carrier losses simultaneously.Additionally, the self-encapsulation effect of this dense interlayer could inhibit volatile ion overflow at high temperatures and improve light and thermal stability.Consequently, the ALD-AlOx modification could significantly improve the PCE of wide-bandgap PSCs from 19.32% to 21.80%. More importantly, a monolithic perovskite-silicon tandem solar cells using AlOx-modified perovskite achieved a PCE of 28.50% with good stability.The resulting 1.55-eV PSC and module also achieved a PCE of 25.08% (0.04 cm2) and 21.01% (aperture area of 15.5 cm2), respectively, proving the universality of the strategy. The study provides an effective way for efficient and stable wide-band gap perovskite and perovskite-silicon TSCs and shed light on large-area inverted PSCs.Figure:The schematic diagram of incorporating AlOx deposited on perovskite surface(image by SARI)<!--!doctype-->