Junwei Han

Bio: Junwei Han is an academic researcher from Central South University. The author has contributed to research in topics: Anode & Materials science. The author has an hindex of 1, co-authored 2 publications receiving 145 citations.

Zincophilic Electrode Interphase with Appended Proton Reservoir Ability Stabilizes Zn Metal Anodes.

Abstract: The rampant dendrites and hydrogen evolution reaction (HER) resulting from the turbulent interfacial evolution at the anode/electrolyte are the main culprits of short lifespan and low Coulombic efficiency of Zn metal batteries. In this work, a versatile protective coating with excellent zincophilic and amphoteric features is constructed on the surface of Zn metal (ZP@Zn) as dendrite-free anodes. This kind of protective coating possesses the advantages of reversible proton storage and rapid desolvation kinetics, thereby mitigating the HER and facilitating homogeneous nucleation concomitantly. Furthermore, the space charge polarization effect promotes charge redistribution to achieve uniform Zn deposition. Accordingly, the ZP@Zn symmetric cell manifests excellent reversibility at an ultrahigh cumulative plating capacity of 4750 mA h cm-2 and stable cycling at 65% depth of discharge (DOD). The ZP@Zn//V6O13 pouch cell also reveals superior cycling stability with a high capacity of 326.6 mA h g-1.

Facing the capacity fading of vanadium-based zinc-ion batteries

Abstract: Because of their high capacity and appropriate structure, vanadium (V)-based materials make up a large proportion of the research on cathodes for rechargeable aqueous zinc–ion batteries (AZIBs). Unfortunately, as a result of catastrophic structural instability and the participation of highly active water, V-based batteries typically suffer from rapid capacity decay, especially under small currents, posing a serious challenge to advancing their commercialization. This review exhaustively elucidates the degradation mechanisms through profiling the process of ion insertion/extraction, and critically summarizes the corresponding strategies. Finally, comprehensive perspectives are proposed from the systemic evaluation criteria and potential investigation direction, which are expected to provide scientific guidelines for beginners in V-based AZIB field.

Graphene membrane hosted compact lithium metal anode enabled by capillary force-tuned lithium infiltration

Abstract: Lithium metal anodes, the promising anodes for next-generation batteries, are troubled by the instability and safety issues induced by the dendrite growth. Three-dimensional hosts are widely used to accommodate lithium metal to solve the above problems. However, they are constantly challenged by large thickness and excess space in the host, lowering the volumetric energy density of batteries. Here, we used the reduced graphene oxide membrane (rGOM) assembled with small graphene oxide sheets as the host and obtained a compact, ultrathin (<20 μm) and free-standing lithium metal-rGO composite anode with good flexibility and high volumetric capacity. The overlap sites derived from the stacking of small size of GO act as abundant diffusion channels for the gas release during the spark reduction process, producing narrow interlamellar space in the rGOM and thus enhancing the capillary molten Li infusion to form a compact composite anode. These sites also guide the uniform deposition of Li metal on the surface and interior of the membrane, effectively suppressing the dendrite growth. This compact composite anode delivers a high volumetric capacity (1223 mAh cm−3) and stable cycling performance in the symmetrical cells and the full cells coupled with high mass loading LiFePO4 cathode under a low N/P ratio.

Challenges in the material and structural design of zinc anode towards high-performance aqueous zinc-ion batteries

Abstract: Rechargeable aqueous metal-ion batteries are very promising as alternative energy storage devices during the post-lithium-ion era because of their green and safe inherent features. Among the different aqueous metal-ion batteries, aqueous zinc-ion batteries (ZIBs) have recently been studied extensively due to their unique and outstanding benefits that hold promise for large-scale power storage systems. However, zinc anode problems in ZIBs, such as zinc dendrites and side reactions, severely shorten the ZIB's cycle lifetime, thus restricting their practical application. Here, we sum up in detail the recent progress on general strategies to suppress zinc dendrites and zinc anode side reactions based on advanced materials and structure design, including the modification of the planar zinc electrode surface layer, internal structural optimization of the zinc bulk electrode, modification of the electrolyte and construction of the multifunctional separator. The various functional materials, structures and battery efficiencies are discussed. Finally, the challenges for ZIBs are identified in the production of functional zinc anodes.

Direct Self‐Assembly of MXene on Zn Anodes for Dendrite‐Free Aqueous Zinc‐Ion Batteries

Abstract: Metallic zinc is a promising anode candidate of aqueous zinc-ion batteries owing to its high theoretical capacity and low redox potential. However, Zn anodes usually suffer from dendrite and side reactions, which will degrade their cycle stability and reversibility. Herein, we developed an in situ spontaneously reducing/assembling strategy to assemble a ultrathin and uniform MXene layer on the surface of Zn anodes. The MXene layer endows the Zn anode with a lower Zn nucleation energy barrier and a more uniformly distributed electric field through the favorable charge redistribution effect in comparison with pure Zn. Therefore, MXene-integrated Zn anode exhibits obviously low voltage hysteresis and excellent cycling stability with dendrite-free behaviors, ensuring the high capacity retention and low polarization potential in zinc-ion batteries.

Deeply understanding the Zn anode behaviour and corresponding improvement strategies in different aqueous Zn-based batteries

Abstract: Owing to the high capacity of the metallic Zn anode and intrinsically safe aqueous electrolyte, aqueous Zn-based batteries are advanced energy storage technology alternatives beyond lithium-ion batteries, providing a cost benefit, high safety, and competitive energy density. There has been a new wave of research interest across the family of Zn batteries, but fundamental understanding of the Zn electrode and its performance improvement still remain inconclusive. Based on the pH value of the electrolyte, Zn-based batteries can be divided into two types, with one adopting alkaline electrolyte and the other mild (including slightly acidic) electrolyte. As the behavior of the Zn electrode in these two distinctive systems is different, their requirements to yield excellent performance are different. In this Review, we present a comprehensive overview of the Zn electrode and its fundamentals in both systems. First, the differences and similarities of the Zn electrode in both systems are outlined. Specific attention is paid to the working principles and technical challenges. Then, Zn electrode issues and recently proposed strategies for each system are summarized and compared. Finally, a perspective on future research directions towards practical applications of aqueous Zn batteries is included.

Fundamentals and perspectives in developing zinc-ion battery electrolytes: a comprehensive review

Abstract: The development of low-cost and high-safety zinc-ion batteries (ZIBs) has been extensively discussed and reviewed in recent years, but the work on the comprehensive discussion and perspectives in developing zinc-ion electrolytes is still relatively lacking. Faced with critical challenges and bottlenecks practically, the viability of ZIBs critically depends on the development of suitable electrolytes and their practical considerations. In this review, a systematic summary with regard to the basic characteristics of zinc-ion electrolytes facing different issues from optimization strategies to the fundamental science of electrolyte/electrode interfaces (EEIs), particularly in the feasible modifications and advanced characterizations of EEIs, has been put forward. Due to the lack of consideration of the practical issues in major academic studies, we have particularly highlighted aspects that mainly focus on the choice of the electrolyte system, dosage of liquid and fluid electrolytes, status of gel and all-solid electrolytes, together with other concerns related to the electrolytes. The final section proposes significant perspectives to guide and promote the development of zinc-ion electrolytes.