Reshaping the conventional Si-based anodes: Silicon (Si) anode has been replacing the conventional graphite (G) anode (~340 mAh/g) due to its highest theoretical capacity (~3000 mAh/g) and relatively safe redox potential (0.1-0.4 V). However, a huge volume expansion (>300%) results in a cracking, particle pulverization, electrical isolation, and solid-electrolyte interphase (SEI) fracture, thus shortening the battery cycle life. Therefore, conventional design principles extensively explored nano-scale material design and its physical blending with graphite anodes (Si/G). Further, the oxidized matrix buffer such a large expansion and resulting SiOx derivatives have been deployed on a commercial scale. Nevertheless, increasing demand for high-energy density and fast-charging necessitate a rational design of high Si-content Si/C and even pure Si anodes. In this perspective, atomic scale materials design to artificially control the composition and local structure are essential.

Relevant publications

• Constructing Pure Si Anodes for Advanced Lithium Batteries, Acc. Chem. Res. (2023) "Featured as a Front Cover"

• Electrochemical scissoring of disordered silicon-carbon composites for high-performance lithium storage, Energy Storage Mater. (2021)

• Infinitesimal sulfur fusion yields quasi-metallic bulk silicon for stable and fast energy storage, Nature Commun. (2019)

• Mechanical mismatch-driven rippling in carbon-coated silicon sheets for stress-resilient battery anodes, Nature Commun. (2018)

Fighting against stress: High stoichiometric and alloying-type anodes entail the detrimental deformation of structure, thus degrading the cell and even triggering the safety issue. Apart from the direct mitigation of structural failure of such electrode materials, polymeric binders, as a chemical glue, dissipate substantial amounts of stress localized onto the surface of electrode materials to the entire electrode and maintain electrode structure to sustain the electrical/ionic pathway and contact of electrode components. The binders further direct the formation of functional interface films to stabilize the charge transfer and ion transport mechanics. Conventional binders such as carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and so on exhibit insufficient adhesion, conductivity, and integration with other components. Therefore, it is highly required to develop reconfigure the polymeric (or hybrid) structure of binders to encompass overall characteristics regardless of anodes or cathodes.

Relevant publications

• Assembling a dense grid structure with green polyhydroxyurethane and a high-capacity Si-based anode for lithium ion batteries, J. Mater. Chem. A (2024) 

• Interface engineering of Si-based anodes with fluorinated binder enabling lean-additive lithium-ion batteries, Energy Storage Mater. (2024)

• Azacyclic Anchor-Enabled Cohesive Graphite Electrodes for Sustainable Anion Storage, Adv. Mater. (2023)

• Layering Charged Polymers Enable Highly Integrated High-Capacity Battery Anodes, Adv. Funct. Mater. (2023) "Featured as a Front Cover"

• Room-Temperature Crosslinkable Natural Polymer Binder for High-Rate and Stable Silicon Anodes, Adv. Funct. Mater. (2020)

• Sliding chains keep particles together, Science (2017)

Divergent strategies for avoidig dendrite: Metal anodes, particularly alkali metals such as  lithium (Li), sodium (Na), and potassium (K), are widely explored for next-generation high-energy-density batteries. However, one of the major challenges limiting their practical application is the formation of dendrites—needle-like metal growths that occur during repeated charge-discharge cycles. These dendrites can lead to short circuits, reduced battery life, and safety hazards such as thermal runaway. Therefore, successful launching of the metal batteries should begin by developing dendrite-less or -free metal anodes, through mutli-dimensional and multiscale strategies, for example, artificial SEI engineering, high affinity host, highly conductive electrolytes, and (quasi-)solid state electrolytes.

Relevant publications

• A polymeric separator membrane with chemoresistance and high Li-ion flux for high-energy-density lithium metal batteries, Energy Storage Mater. (2022)

• Vinyl-Integrated In Situ Cross-Linked Composite Gel Electrolytes for Stable Lithium Metal Anodes, ACS Appl. Energy  Mater. (2021)

• Homogeneous Li deposition through the control of carbon dot-assisted Li-dendrite morphology for high-performance Li-metal batteries, J. Mater. Chem. A (2019)

Beyond fast-charging technology : Traditional rocking-chair batteries are based on intercalation chemistry of active host materials which impede the charge transport reactions and consequently limit the charging time of batteries (typically longer than 1 hour). Single-cation batteries should expect an entire travel length of charge carriers across every cell components that exceed 200 micrometer in general and become severe even in case of solid batteries. To overcome the fundamental challenges for charging time, we strive for utilizing both cation and anion for charge storage. Anion storage into the cathode at high redox potential (>5V) features high capacity as well as the fast-charging capability which can be enabled by the rational design of electrolytes, interface and anion-hosting materials.

Relevant publications

• Charge Separation Induced by Asymmetric Surface Charge Effects in Quasi-Solid State Electrolyte for Sustainable Anion Storage, Adv. Energy Mater. (2024)

• Azacyclic Anchor-Enabled Cohesive Graphite Electrodes for Sustainable Anion Storage, Adv. Mater. (2023)

• Electrolyte-mediated nanograin intermetallic formation enables superionic conduction and electrode stability in rechargeable batteries, Energy Storage Mater. (2021)

Keeping pace with sustainable society: Sustainable batteries are essential for the future of clean energy, electric vehicles, and grid storage. Research and innovation in alternative materials, efficient recycling, and eco-friendly manufacturing processes will drive the transition toward greener and more ethical battery technologies. For example, our research group has devoted to 1) Aqueous batteries, 2) Multivalent metal batteries, and 3) Organic batteries. 

Relevant publications

• Toward Long-life High-voltage Aqueous Li-ion Batteries: From Solvation Chemistry to Solid-electrolyte-interphase Layer Optimization Against Electron Tunneling Effect, Adv. Mater. (2025)

• From Bulk to Interface: Solvent Exchange Dynamics and Their Role in Ion Transport and the Interfacial Model of Rechargeable Magnesium Batteries, J. Am. Chem. Soc. (2024)

• Nonporous Oxide-Terminated Multicomponent Bulk Anode Enabling Energy-Dense Sodium-Ion Batteries, ACS Appl. Mater. Interfaces (2023)

• Lithium Accommodation in a Redox-Active Covalent Triazine Framework for High Areal Capacity and Fast-Charging Lithium-Ion Batteries,  Adv. Funct. Mater. (2020)

• Three-Dimensional Monolithic Organic Battery Electrodes, ACS Nano (2019)