Selected Works:

"Unveiling Multifunctional Synthetic Boundaries for Enhanced Mechanical and Electrochemical Performance in Densified Thick Composite Electrodes,” Nature Communications, 2025, 16, 9489.

"Multilayer Composite Electrodes for Simultaneously Improved Mechanical and Electrochemical Performance," ACS Applied Materials & Interfaces, 2025, 025, 17, 6, 9452–9459.

"Probing Cold Sintering-Regulated Interfaces and Integration of Polymer-in-Ceramic Solid-State Electrolytes," Materials Today Energy, 2025, 101829.

"Cold Sintering of Halide-in-Oxide Composite Solid-State Electrolytes," ACS Applied Materials & Interfaces, 2024, 16, 49, 67635.

"Alignment Does Matter: Bulk Electrodes to Revolutionize Conventional Lithium Ion Batteries," Carbon, 2023, 206, 105-113. (Front Cover)

"Multifunctional Composite Designs for Structural Energy Storage," Battery Energy, 2023, 2, 20230023.

"Direct Recycling for Advancing Sustainable Battery Solutions," Materials Today Energy, 2023, 38, 101434. (Front Cover)

"Hierarchical 3D Electrode for Electrochemical Energy Storage," Nature Reviews Materials, 2019, 4, 45-60.

"Three-Dimensional Holey-Graphene/Niobia Composite Architectures for Ultrahigh-Rate Energy Storage," Science, 2017, 356, 599-604.

"A Hyperaccumulation Pathway to Three-Dimensional Hierarchical Porous Nanocomposites for Highly Robust High-Power Electrodes," Nature Communications, 2016, 7, 13432.

"High Rate Lithiation-induced Reactivation of Mesoporous Hollow Spheres for Long-lived Lithium Ion Batteries," Nature Communications, 2014, 5, 4526.

Current Projects

Operando DIC Characterization of Chemo–Electro–Mechanical Coupling to Investigate Electromechanical Degradation Mechanisms

Personnel: Ta-Wei Wang (Ph.D. student)

We have developed an operando dynamic strain mapping technique using digital image correlation (DIC) to capture the full-field distribution of electrochemically induced strains during battery cycling. This innovative in-situ imaging method evaluates the homogeneity and state of charge (SOC) of composite electrodes as they undergo chemo-electro-mechanical coupling. For example, real-time imaging provides full-field dynamic strain mapping of the NMC 811 cathode during the delithiation process, offering valuable insights into mechanochemical degradation. Unlike other advanced operando techniques that rely on synchrotron X-rays, lasers, or visible light, our DIC-based approach utilizes an economical camera, striking an optimal balance between a large field of view, high microscopic resolution, rapid imaging rates, and detailed spatial analysis of heterogeneities.

B. Nie†, S. Lee†, T. Wang, T. Liu, J. Li*, and H. Sun*, "Unveiling Multifunctional Synthetic Boundaries for Enhanced Mechanical and Electrochemical Performance in Densified Thick Composite Electrodes," Nature Communications, 2025, 16, 9489.

Design and Manufacturing of Hierarchically Structured Electrodes with Simultaneously Enhanced Mechanical and Electrochemical Performance

Personnel: Seok Woo Lee, Bo Nie (Ph.D. students)

High energy-density rechargeable batteries are crucial for sustainable energy solutions, as they reduce reliance on fossil fuels and lower greenhouse gas emissions. Increasing electrode thickness is a viable strategy to boost energy density at the device level. However, simply increasing electrode thickness introduces charge transport limitations and exacerbates mechanochemical degradation. To address these fundamental challenges, we fabricate hierarchically structured thick electrodes, including densified composite electrodes with controlled secondary boundary phase, and multilayer-structured electrodes. These hierarchical designs offer several key advantages: (1) strain-resistant properties that mitigate mechanochemical degradation; (2) enhanced charge transport, optimizing the balance of trade-off battery performance metrics (areal, volumetric, and gravimetric energy densities); (3) the ability for direct recycling of structured electrodes by breaking and reforming synthetic interfacial phases; and (4) the potential for structural battery applications through the “structural plus” concept.

B. Nie, T. Wang, S. Lee, and H. Sun*, "Multilayer Composite Electrodes for Simultaneously Improved Mechanical and Electrochemical Performance," ACS Applied Materials & Interfaces, 2025, 025, 17, 6, 9452–9459.

B. Nie, D. Sanchez, M. Alcoutlabi, T. Liu, G. Wang, and H. Sun*, “Liquid Crystal Phase-Regulated Hierarchical Structures for High-Performance Silicon-Graphene Anodes,” ACS Applied Nano Materials, 2023, 6, 18757 - 18766. (Front Cover)

B. Nie, J. Lim, T. Liu, J. Zhu, J. Liang, and H. Sun*, "Multifunctional Composite Designs for Structural Energy Storage," Battery Energy, 2023, 2, 20230023.

B. Nie, M. Li, T. Yao, H. Yang, L. Duan, J. Zhang, G. Xin, T. Liu, H. Sun*, and J. Lian*, "Alignment Does Matter: Bulk Electrodes to Revolutionize Conventional Lithium Ion Batteries," Carbon, 2023, 206, 105-113. (Front Cover)

H. Sun et al., "Three-Dimensional Holey-Graphene/Niobia Composite Architectures for Ultrahigh-Rate Energy Storage," Science, 2017, 356, 599-604.

Interface Engineering for Solid State Batteries

Personnel: Seok Woo Lee, Linrui Duan, and Bo Nie (Ph.D. students)

Solid-state batteries (SSBs) have attracted enormous attention to increase energy density and eliminate safety concerns associated with flammable liquid electrolytes in current Li-ion batteries. However, fabricating solid-state electrolytes (SSEs) and integrated devices presents numerous challenges, especially due to limited methods for addressing interfacial issues between ionic conductor building blocks (such as grains or secondary particles) and other active or passive materials in the SSB system. To overcome these challenges, we investigate various types of SSEs, including ceramic, polymer-in-ceramic (PIC) or ceramic-in-polymer (CIP) composite, and polymer electrolytes. Particularly, we explore in-situ electrochemical impedance spectroscopy (EIS) as an inline monitoring tool during SSE integration, providing deeper insights into the fabrication process, interface evolution, and process-structure-property relationships.

B.. Nie, T. Wang, S. Lee, J. Zhang, and H. Sun*, "Probing Cold Sintering-Regulated Interfaces and Integration of Polymer-in-Ceramic Solid-State Electrolytes," Materials Today Energy, 2025, 101829.

L. Duan, J. Zhang, M. Alcoutlabi, and H. Sun*, "Tailoring Gel Polymer Electrolytes for Advancing Quasi-Solid-State Batteries," Advanced Materials Interfaces , 2025, 12, 2401028.

B. Nie, T. Wang, S. Lee, and H. Sun*, "Cold Sintering of Halide-in-Oxide Composite Solid-State Electrolytes," ACS Applied Materials & Interfaces, 2024, 16, 49, 67635.

Direct Recycling in Closed-Loop Eco-Manufacturing Processes for Functional Composites

Personnel: Juchen Zhang and Ta-Wei Wang (Ph.D. students)

Lithium-ion batteries (LIBs) have been produced extensively to meet the escalating demand for sustainable energy solutions in consumer electronics, renewable energy integration, and electric transportation. However, the accumulation of end-of-life LIBs has raised concerns regarding the environmental impact and the sustainability of their manufacturing processes. To address these issues, battery recycling has emerged as a key solution, offering both environmental protection and enhanced manufacturing sustainability. Unlike traditional recycling methods, which rely on high-temperature smelting and acid-leaching, direct recycling is gaining traction for its economic and environmental advantages. In this research, we develop direct recycling methods by breaking and reforming synthetic boundary phases to recover and reuse active materials or ionic conductors from end-of-life composite electrodes or solid-state electrolytes. This approach supports a closed-loop eco-manufacturing model, advancing sustainable battery technology.

J. Zhang, E. Gomez*, and H. Sun*, "Nano-Sized Polymer-Assisted Cold Sintering and Recycling of Ceramic Composites," MRS Communications, 2024, 43579.

T. Wang, and H. Sun* "Direct Recycling for Advancing Sustainable Battery Solutions," Materials Today Energy, 2023, 38, 101434. (Front Cover)

Beyond Li-Ion Batteries

Personnel: Yifang Ding (Ph.D. student)

While lithium-ion batteries (LIBs) currently dominate the energy storage industry, there are significant concerns about the limited global lithium (Li) resources, their uneven geographical distribution, and associated safety risks. In contrast, alternative battery technologies—such as sodium-ion (SIBs), potassium-ion (PIBs), and zinc-ion batteries (ZIBs)—are gaining attention as promising solutions due to the high abundance and low cost of these materials. However, despite their advantages, the performance metrics of these alternatives (e.g., energy density, power density, cycling stability) still fall short of meeting the rapidly increasing demands of modern applications. To address this, we develop advanced electrode materials and devices for these next-generation metal-ion batteries, aiming to elevate their performance to rival or surpass that of current LIBs, thus making them viable candidates for sustainable, high-performance energy storage solutions.

J. Cai†, Y. Ding†, R. Bai, C. Zhang, X. Zhang, H. Sun*, and G. Wang*, "Versatile Potassium Vanadium Fluorophosphate (KVPO4F) Composites as Dual-Function Cathode and Anode Materials for Potassium-Ion Hybrid Capacitors," Journal of Colloid and Interface Science, 2023, 651, 534-543.

Y. Wang†, Y. Ding†, J. Gao, X. Zhang, H. Sun*, and G. Wang*, “Microwave-Regulated Bi Nanoparticles on Carbon Nanotube Networks as a Freestanding Electrode for Flexible Sodium-Ion Capacitors,” Journal of Colloid and Interface Science, 2023, 643, 420-427.

S. Li, H. Chen, Q. Zhang, H. Deng, S. Chen, X. Shen, Y. Yuan, Y. Ding, Y. Cheng*, H. Sun*, J. Zhu*, and B. Lu, “Enhanced Potassium-Ion Storage Performance of Bimetallic-Sulfide Based on Regulatory Reaction Mechanism,” Chemical Engineering Journal, 2023, 466, 143342