More Like this

1. Intercalation‐Induced Phase Transitions in Ferroelectric α‐In ₂ Se ₃

   https://doi.org/10.1002/advs.202513712  

   He, Xin; Gong, Zhihao; Wang, Tao; Wang, Baoyu; Liu, Chen; Wang, Ding; Ma, Yinchang; Feng, Pu; Zhang, Chenhui; Hu, Weijin; et al (December 2025, Advanced Science)

   Abstract Specific ions can be intercalated into functional materials using the electrolyte gating technique, which has been widely used to regulate channel conductance in transistors and develop low‐power neuromorphic devices. However, in these devices, fundamental exploration of ion intercalation‐induced structural phase transitions remains largely overlooked and rarely explored. Here, the lithium‐based electrolyte gating technique is used to probe the collective interactions between ions, lattices, and electrons in a van der Waals ferroelectric semiconductor α‐In₂Se₃. Using a polymer electrolyte as the lithium‐ion reservoir and α‐In₂Se₃as the channel material, the intercalated lithium concentration via a gate electric field is modulated. This manipulation drives a phase transition in α‐In₂Se₃from a ferroelectric semiconductor to a dirty metal and finally to a metal, accompanied by a structural transformation. Concurrently, with enhanced intercalation, the ferroelectric hysteresis window progressively narrows and eventually disappears, indicating the evolution from switchable to non‐switchable polarization. This study represents a promising platform for the artificial construction of correlated material systems, enabling a systematic investigation into the interaction of ferroelectricity and electronic conduction using ion intercalation. 

   more » « less
2. Polymorphism of low dimensional boron nanomaterials driven by electrostatic gating: a computational discovery

   https://doi.org/10.1039/C9NR10774F  

   Jiao, Yalong; Ma, Fengxian; Gu, Jinxing; Chen, Zhongfang; Du, Aijun (May 2020, Nanoscale)

   null (Ed.)

   The successful synthesis of two-dimensional (2D) boron sheets typically relies on the utilization of a silver surface, which acts as a gated substrate compensating for the electron-deficiency of boron. However, how the structures of one-dimensional (1D) boron are affected by the gating effect remains unclear. By means of an unbiased global minimum structure search and density functional theory (DFT) computations, we discovered the coexistence of 2D boron sheets and 1D ribbons triggered by electrostatic gating. Specifically, at a low excess charge density level (<0.1 e per atom), 2D boron sheets dominate the low energy configurations. As the charge density increases (>0.3 e per atom), more 1D boron ribbons emerge, while the number of 2D layers is reduced. Additionally, a number of low-lying 1D boron ribbons were discovered, among which a flat borophene-like ribbon (FBR) was predicted to be stable and possess high mechanical strength. Moreover, the electride Ca 2 N was identified as an ideal substrate for the fabrication of the FBR because of its ability to supply a strong electrostatic field. This work bridges the gap between 2D and 1D boron structures, reveals the polymorphism of 1D boron ribbons under the electrostatic gating effect, and in general provides broad implications for future synthesis and applications of low-dimensional boron materials. 

   more » « less
3. Is the Chemisorbed CO ₂ in Ionic Liquid Electrolytes Active for Electrochemical Utilization? A Case Study on Carboxylate and Carbamate Speciation

   https://doi.org/10.1149/1945-7111/addf83  

   Coskun, Oguz Kagan; Dongare, Saudagar; Gurkan, Burcu E (June 2025, Journal of The Electrochemical Society)

   This study examines the activity of chemisorbed CO₂species in the microenvironment formed by bifunctional ionic liquids (ILs) in the reactive capture and conversion (RCC) of CO₂to CO on silver. Comparative electroanalytical measurements with imidazolium based ILs were performed to probe the impact of electrostatic interactions, anion and cation basicity, and hydrogen bonding on RCC. Particularly, ILs with 1-ethyl-3-methylimidazolium ([EMIM]⁺) and 1-ethyl-2,3-dimethylimidazolium ([EMMIM]⁺) cations and aprotic heterocyclic anions of 2-cyanopyrrolide ([2-CNpyr]) and 1,2,4-triazolide ([124-Triz]) were examined for RCC. It was found that anion–CO₂carbamate complexes facilitate RCC at significantly lower overpotentials compared to cation–CO₂carboxylate complexes. Additionally, [EMIM]⁺was found to better stabilize anion–CO₂complexes at the interface than [EMMIM]⁺. Furthermore, it was found that 2-CNpyrH that naturally forms during CO₂absorption competes for electrode surface adsorption with the anion–CO₂carbamate complex, thereby reducing the electrochemical activity of the anion–CO₂complex. These results highlight the importance of IL structure in tuning the interfacial interactions and suggest that ILs with anion-dominated CO₂chemisorption enhances CO₂utilization in RCC applications. 

   more » « less
4. What controls electrostatic vs electrochemical response in electrolyte-gated materials? A perspective on critical materials factors

   https://doi.org/10.1063/5.0087396  

   Leighton, Chris; Birol, Turan; Walter, Jeff (April 2022, APL Materials)

   Electrolyte-gate transistors are a powerful platform for control of material properties, spanning semiconducting behavior, insulator-metal transitions, superconductivity, magnetism, optical properties, etc. When applied to magnetic materials, for example, electrolyte-gate devices are promising for magnetoionics, wherein voltage-driven ionic motion enables low-power control of magnetic order and properties. The mechanisms of electrolyte gating with ionic liquids and gels vary from predominantly electrostatic to entirely electrochemical, however, sometimes even in single material families, for reasons that remain unclear. In this Perspective, we compare literature ionic liquid and ion gel gating data on two rather different material classes—perovskite oxides and pyrite-structure sulfides—seeking to understand which material factors dictate the electrostatic vs electrochemical gate response. From these comparisons, we argue that the ambient-temperature anion vacancy diffusion coefficient ( not the vacancy formation energy) is a critical factor controlling electrostatic vs electrochemical mechanisms in electrolyte gating of these materials. We, in fact, suggest that the diffusivity of lowest-formation-energy defects may often dictate the electrostatic vs electrochemical response in electrolyte-gated inorganic materials, thereby advancing a concrete hypothesis for further exploration in a broader range of materials. 

   more » « less
5. Inhibition of lithium dendrite growth with highly concentrated ions: cellular automaton simulation and surrogate model with ensemble neural networks

   https://doi.org/10.1039/d1me00150g  

   Gao, Tong; Qian, Ziwei; Chen, Hongbo; Shahbazian-Yassar, Reza; Nakamura, Issei (March 2022, Molecular Systems Design & Engineering)

   We have developed a lattice Monte Carlo (MC) simulation based on the diffusion-limited aggregation model that accounts for the effect of the physical properties of small ions such as inorganic ions and large salt ions that mimic ionic liquids (ILs) on lithium dendrite growth. In our cellular automaton model, molecular and atomistic details are largely coarse-grained to reduce the number of model parameters. During lithium deposition, the cations of the salt and ILs form positively charged electrostatic shields around the tip of the dendrites, and the anions of the salt and ILs form negative local potential lumps in adjacent areas to the dendrite. Both of the effects change the distribution of the electrostatic potential and notably inhibit dendrite formation between electrodes. The applied voltage and the physical properties of the salt ions and ILs, such as the size of the ions, the size asymmetry between the cation and anion, the dielectric constant, the excluded volume of the ions, and the model parameter η , notably affect electric-field screening and hence the variation in the local potential, resulting in substantial changes in the aspect ratio and the average height of the dendrites. Our present results suggest that the large salts such as ILs more significantly inhibit the dendrite growth than the small ions, mainly because the ions highly dissociated in ILs can participate in electrostatic shielding to a greater degree. To reduce the computational complexity and burden of the MC simulation, we also constructed a surrogate model with ensemble neural networks. 

   more » « less