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13 pages, 1645 KiB

Open AccessArticle

Machine-Learning Model Prediction of Ionic Liquids Melting Points

by Zafer Acar, Phu Nguyen and Kah Chun Lau

Appl. Sci. 2022, 12(5), 2408; https://doi.org/10.3390/app12052408 - 25 Feb 2022

Cited by 9 | Viewed by 3209

Abstract

Ionic liquids (ILs) have great potential for application in energy storage and conversion devices. They have been identified as promising electrolytes candidates in various battery systems. However, the practical application of many ionic liquids remains limited due to the unfavorable melting points ( [...] Read more.

Ionic liquids (ILs) have great potential for application in energy storage and conversion devices. They have been identified as promising electrolytes candidates in various battery systems. However, the practical application of many ionic liquids remains limited due to the unfavorable melting points (T_m) which constrain the operating temperatures of the batteries and exhibit unfavorable transport property. To fine tune the T_m of ILs, a systematic study and accurate prediction of T_m of ILs is highly desirable. However, the T_m of an IL can change considerably depending on the molecular structures of the anion and cation and their combination. Thus, a fine control in T_m of ILs can be challenging. In this study, we employed a deep-learning model to predict the T_m of various ILs that consist of different cation and anion classes. Based on this model, a prediction of the melting point of ILs can be made with a reasonably high accuracy, achieving an R² score of 0.90 with RMSE of ~32 K, and the T_m of ILs are mostly dictated by some important molecular descriptors, which can be used as a set of useful design rules to fine tune the T_m of ILs. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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16 pages, 5079 KiB

Open AccessArticle

The Influence of Transitional Metal Dopants on Reducing Chlorine Evolution during the Electrolysis of Raw Seawater

by Prajwal Adiga, Nathan Doi, Cindy Wong, Daniel M. Santosa, Li-Jung Kuo, Gary A. Gill, Joshua A. Silverstein, Nancy M. Avalos, Jarrod V. Crum, Mark H. Engelhard, Kelsey A. Stoerzinger and Robert Matthew Asmussen

Appl. Sci. 2021, 11(24), 11911; https://doi.org/10.3390/app112411911 - 15 Dec 2021

Cited by 4 | Viewed by 3319

Abstract

Electrocatalytic water splitting is a possible route to the expanded generation of green hydrogen; however, a long-term challenge is the requirement of fresh water as an electrolyzer feed. The use of seawater as a direct feed for electrolytic hydrogen production would alleviate fresh [...] Read more.

Electrocatalytic water splitting is a possible route to the expanded generation of green hydrogen; however, a long-term challenge is the requirement of fresh water as an electrolyzer feed. The use of seawater as a direct feed for electrolytic hydrogen production would alleviate fresh water needs and potentially open an avenue for locally generated hydrogen from marine hydrokinetic or off-shore power sources. One environmental limitation to seawater electrolysis is the generation of chlorine as a competitive anodic reaction. This work evaluates transition metal (W, Co, Fe, Sn, and Ru) doping of Mn-Mo-based catalysts as a strategy to suppress chlorine evolution while sustaining catalytic efficiency. Electrochemical evaluations in neutral chloride solution and raw seawater showed the promise of a novel Mn-Mo-Ru electrode system for oxygen evolution efficiency and enhanced catalytic activity. Subsequent stability testing in a flowing raw seawater flume highlighted the need for improved catalyst stability for long-term applications of Mn-Mo-Ru catalysts. This work highlights that elements known to be selective toward chlorine evolution in simple oxide form (e.g., RuO₂) may display different trends in selectivity when used as isolated dopants, where Ru suppressed chlorine evolution in Mn-based catalysts. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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16 pages, 6069 KiB

Open AccessArticle

Spherical Polydopamine-Modified Carbon-Felt Cathode with an Active Indole Structure for Efficient Hydrogen Peroxide Electroproduction

by Lei Chen, Sicheng Yuan, Huaiyuan Wang, Yanji Zhu, Dengyu Fu and Zhenggui Li

Appl. Sci. 2021, 11(12), 5371; https://doi.org/10.3390/app11125371 - 9 Jun 2021

Cited by 2 | Viewed by 1964

Abstract

As one of the most promising methods for H₂O₂ production, H₂O₂ electroproduction has received increasingly more attention. In this study, a spherical particle polydopamine (pDA) modified carbon felt (noted as ht-pDA/ACF) for H₂O₂ production [...] Read more.

As one of the most promising methods for H₂O₂ production, H₂O₂ electroproduction has received increasingly more attention. In this study, a spherical particle polydopamine (pDA) modified carbon felt (noted as ht-pDA/ACF) for H₂O₂ production was fabricated. At a constant potential of 2.0 V and pH of 1.0, the H₂O₂ production of the ht-pDA/ACF cathode reached 220 mg/L after 6 h of electrolyzing, compared to the 30 mg/L H₂O₂ production of raw carbon felt. Firstly, the spherical pDA exposes more active sites that are favorable to the 2e⁻ ORR compared to pDA film. Secondly, the ring cleavage and re-cyclization of indole structure in the pDA during electrolyzing could form the radicals that act as the intermediate to the H₂O₂ formation. This research exhibits a low-cost method to modify carbon materials for effective H₂O₂ electroproduction. The ht-pDA/ACF cathode is promising for green H₂O₂ production and wastewater treatment. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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9 pages, 2737 KiB

Open AccessArticle

Influence of Heterointerfaces on the Kinetics of Oxygen Surface Exchange on Epitaxial La_1.85Sr_0.15CuO₄ Thin Films

by Gene Yang, So-Yeun Kim, Changhee Sohn, Jong K. Keum and Dongkyu Lee

Appl. Sci. 2021, 11(9), 3778; https://doi.org/10.3390/app11093778 - 22 Apr 2021

Cited by 8 | Viewed by 1792

Abstract

Considerable attention has been directed to understanding the influence of heterointerfaces between Ruddlesden–Popper (RP) phases and ABO₃ perovskites on the kinetics of oxygen electrocatalysis at elevated temperatures. Here, we report the effect of heterointerfaces on the oxygen surface exchange kinetics by employing [...] Read more.

Considerable attention has been directed to understanding the influence of heterointerfaces between Ruddlesden–Popper (RP) phases and ABO₃ perovskites on the kinetics of oxygen electrocatalysis at elevated temperatures. Here, we report the effect of heterointerfaces on the oxygen surface exchange kinetics by employing heteroepitaxial oxide thin films formed by decorating LaNiO₃ (LNO) on La_1.85Sr_0.15CuO₄ (LSCO) thin films. Regardless of LNO decoration, tensile in-plane strain on LSCO films does not change. The oxygen surface exchange coefficients (k_chem) of LSCO films extracted from electrical conductivity relaxation curves significantly increase with partial decorations of LNO, whereas full LNO coverage leads to the reduction in the k_chem of LSCO films. The activation energy for oxygen exchange in LSCO films significantly decreases with partial LNO decorations in contrast with the full coverage of LNO. Optical spectroscopy reveals the increased oxygen vacancies in the partially covered LSCO films relative to the undecorated LSCO film. We attribute the enhanced oxygen surface exchange kinetics of LSCO to the increased oxygen vacancies by creating the heterointerface between LSCO and LNO. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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26 pages, 3573 KiB

Open AccessArticle

Intercalating Sn/Fe Nanoparticles in Compact Carbon Monolith for Enhanced Lithium Ion Storage

by Jie Deng, Yu Dai, Hui Dai and Luming Li

Appl. Sci. 2020, 10(7), 2220; https://doi.org/10.3390/app10072220 - 25 Mar 2020

Cited by 2 | Viewed by 2530

Abstract

Given its high-capacity of multielectron (de-)lithiation, SnO₂ is deemed as a competitive anode substance to tackle energy density restrictions of low-theoretical-capacity traditional graphite. However, its pragmatic adhibition seriously encounters poor initial coulombic efficiency from irreversible Li₂O formation and drastic volume [...] Read more.

Given its high-capacity of multielectron (de-)lithiation, SnO₂ is deemed as a competitive anode substance to tackle energy density restrictions of low-theoretical-capacity traditional graphite. However, its pragmatic adhibition seriously encounters poor initial coulombic efficiency from irreversible Li₂O formation and drastic volume change during repeated charge/discharge. Here, an applicable gel pyrolysis methodology establishes a SnO₂/Fe₂O₃ intercalated carbon monolith as superior anode materials for Li ion batteries to effectively surmount problems of SnO₂. Its bulk-like, micron-sized, compact, and non-porous structures with low area surfaces (14.2 m² g⁻¹) obviously increase the tap density without compromising the transport kinetics, distinct from myriad hierarchically holey metal/carbon materials recorded till date. During the long-term Li⁺ insertion/extraction, the carbon matrix not only functions as a stress management framework to alleviate the stress intensification on surface layers, enabling the electrode to retain its morphological/mechanic integrity and yielding a steady solid electrolyte interphase film, but also imparts very robust connection to stop SnO₂ from coarsening/losing electric contact, facilitating fast electrolyte infiltration and ion/electron transfer. Besides, the closely contacted and evenly distributed Fe₂O₃/SnO₂ nanoparticles supply additional charge-transfer driving force, thanks to a built-in electric field. Benefiting from such virtues, the embedment of binary metal oxides in the dense carbons enhances initial Coulombic efficiency up to 67.3%, with an elevated reversible capacity of 726 mAh/g at 0.2 A/g, a high capacity retention of 84% after 100 cycles, a boosted rate capability between 0.2 and 3.2 A g⁻¹, and a stable cycle life of 466 mAh/g over 200 cycles at 1 A g⁻¹. Our scenario based upon this unique binary metal-in-carbon sandwich compact construction to achieve the stress regulation and the so-called synergistic effect between metals or metal oxides and carbons is economically effective and tractable enough to scale up the preparation and can be rifely employed to other oxide anodes for ameliorating their electrochemical properties. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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16 pages, 5299 KiB

Open AccessArticle

Porous Doped Carbons from Anthracite for High-Performance Supercapacitors

by Jie Deng, Zhu Peng, Zhe Xiao, Shuang Song, Hui Dai and Luming Li

Appl. Sci. 2020, 10(3), 1081; https://doi.org/10.3390/app10031081 - 6 Feb 2020

Cited by 13 | Viewed by 2910

Abstract

Carbon-based materials, as some of the most important electrode materials for supercapacitors (SC), have spurred enormous attentions. Now, it is highly desirable but remains an open challenge to design stable and high-capacity carbons for further enhancing supercapacitive function. Here, a facile chemical activation [...] Read more.

Carbon-based materials, as some of the most important electrode materials for supercapacitors (SC), have spurred enormous attentions. Now, it is highly desirable but remains an open challenge to design stable and high-capacity carbons for further enhancing supercapacitive function. Here, a facile chemical activation recipe is introduced to develop biomass-derived functional carbons using cheap and abundant natural resources, anthracite, as the heteroatom-rich carbon sources, and potassium hydroxide (KOH) as activator. These porous carbons have high BET surface areas of roughly 2814 m² g⁻¹, large pore volumes of up to 1.531 cm³ g⁻¹, and a high porosity that combines micro- and small-sized mesopores. The optimal nanocarbon features two additional outstanding virtues: an appropriate N-doping level (2.77%) and a uniform pore size distribution in the narrow range of 1–4 nm. Synergy of the above unique structural traits and desirable chemical composition endows resultant samples with the much boosted supercapacitive property with remarkable specific capacitance at varied current densities (e.g., 325 F g⁻¹ at 0.5 A/g), impressive energy/power density, and long cycling stability over 5000 cycles at 10 A g⁻¹ (92% capacity retention). When constructing the symmetric supercapacitor utilizing a common neutral Na₂SO₄ electrolyte that can strongly circumvent the corrosion effect occurring in the strong acid/alkaline solutions, both an elevated operation voltage at 1.8 V and a fascinating energy density of 23.5 Wh kg⁻¹ are attained. The current study paves the way to explore the stable, efficient, and high-voltage SC assembled by the anthracite-derived porous doped nanocarbons for a wide spectrum of applications like automobiles, vehicle devices, and so on. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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49 pages, 4656 KiB

Open AccessReview

Advances in Materials Design for All-Solid-state Batteries: From Bulk to Thin Films

by Gene Yang, Corey Abraham, Yuxi Ma, Myoungseok Lee, Evan Helfrick, Dahyun Oh and Dongkyu Lee

Appl. Sci. 2020, 10(14), 4727; https://doi.org/10.3390/app10144727 - 9 Jul 2020

Cited by 27 | Viewed by 9762

Abstract

All-solid-state batteries (SSBs) are one of the most fascinating next-generation energy storage systems that can provide improved energy density and safety for a wide range of applications from portable electronics to electric vehicles. The development of SSBs was accelerated by the discovery of [...] Read more.

All-solid-state batteries (SSBs) are one of the most fascinating next-generation energy storage systems that can provide improved energy density and safety for a wide range of applications from portable electronics to electric vehicles. The development of SSBs was accelerated by the discovery of new materials and the design of nanostructures. In particular, advances in the growth of thin-film battery materials facilitated the development of all solid-state thin-film batteries (SSTFBs)—expanding their applications to microelectronics such as flexible devices and implantable medical devices. However, critical challenges still remain, such as low ionic conductivity of solid electrolytes, interfacial instability and difficulty in controlling thin-film growth. In this review, we discuss the evolution of electrode and electrolyte materials for lithium-based batteries and their adoption in SSBs and SSTFBs. We highlight novel design strategies of bulk and thin-film materials to solve the issues in lithium-based batteries. We also focus on the important advances in thin-film electrodes, electrolytes and interfacial layers with the aim of providing insight into the future design of batteries. Furthermore, various thin-film fabrication techniques are also covered in this review. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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21 pages, 4273 KiB

Open AccessReview

Recent Advances in Lithiophilic Porous Framework toward Dendrite-Free Lithium Metal Anode

by Rajesh Pathak, Yue Zhou and Qiquan Qiao

Appl. Sci. 2020, 10(12), 4185; https://doi.org/10.3390/app10124185 - 18 Jun 2020

Cited by 36 | Viewed by 10367

Abstract

Rechargeable lithium metal anode (LMA) based batteries have attracted great attention as next-generation high-energy-density storage systems to fuel the extensive practical applications in portable electronics and electric vehicles. However, the formation of unstable solid-electrolyte- interphase (SEI) and growth of lithium dendrite during plating/stripping [...] Read more.

Rechargeable lithium metal anode (LMA) based batteries have attracted great attention as next-generation high-energy-density storage systems to fuel the extensive practical applications in portable electronics and electric vehicles. However, the formation of unstable solid-electrolyte- interphase (SEI) and growth of lithium dendrite during plating/stripping cycles stimulate safety concern, poor coulombic efficiency (CE), and short lifespan of the lithium metal batteries (LMBs). To address these issues, the rational design of micro/nanostructured Li hosts are widely adopted in LMBs. The high surface area of the interconnected conductive framework can homogenize the Li-ion flux distribution, lower the effective current density, and provides sufficient space for Li accommodation. However, the poor lithiophilicity of the micro/nanostructure host cannot govern the initial lithium nucleation, which leads to the non-uniform/dendritic Li deposition and unstable SEI formation. As a result, the nucleation overpotential and voltage hysteresis increases, which eventually leads to poor battery cycling performance. Thus, it is imperative to decorate a micro/nanostructured Li host with lithiophilic coatings or seeds for serving as a homogeneous nucleation site to guide the uniform lithium deposition. In this review, we summarize research progress on porous metal and non-metal based lithiophilic micro/nanostructured Li hosts. We present the synthesis, structural properties, and the significance of lithiophilic decorated micro/nanostructured Li host in the LMBs. Finally, the perspectives and critical challenges needed to address for the further improvement of LMBs are concluded. Full article

(This article belongs to the Special Issue Design of Advanced Materials for Energy Conversion and Storage Applications)

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