目录 | 《电化学》2022年第2期（电化学前沿专辑-上）文章速览

本期收录8篇电化学研究领域各方向的综述和研究论文。扫描或识别二维码，免费查看、下载文献的PDF全文。

In electrochemistry, perhaps also in other time-honored scientific disciplines, knowledge labelled classical usually attracts less attention from beginners, especially those pressured or tempted to quickly jam into research fronts that are labelled, not always aptly, modern. In fact, it is a normal reaction to the burden of history and the stress of today. Against this context, accessible tutorials on classical knowledge are useful, should some realize that taking a step back could be the best way forward. This is the driving force of this article themed at physicochemical modelling of the electric (electrochemical) double layer (EDL). We begin the exposition with a rudimentary introduction to key concepts of the EDL, followed by a brief introduction to its history. We then elucidate how to model the EDL under equilibrium, using firstly the orthodox Gouy-Chapman-Stern model, then the symmetric Bikerman model, and finally the asymmetric Bikerman model. Afterwards, we exemplify how to derive a set of equations governing the EDL dynamics under nonequilibrium conditions using a unifying grand-potential approach. In the end, we expound on the definition and mathematical foundation of electrochemical impedance spectroscopy (EIS), and present a detailed derivation of an EIS model for a simple EDL. We try to avoid the omission of supposedly ‘trivial’ information in the derivation of models, hoping that it can ease the access to the wonderful garden of physical electrochemistry.

Oxygen reduction reaction (ORR) in alkaline electrolytes is an important electrochemical process for metal-air batteries and anion exchange membrane fuel cells (AEMFCs). However, the sluggish kinetics spurs intensive research on searching robust electrocatalysts. Non-precious metal catalysts (NPMCs) that can circumvent the cost and scarcity issues associated with platinum (Pt)-based materials have been pursued and the challenges lie in the performance improvement to rival Pt-based benchmarks. As the composition and structure of the NPMCs have a significant impact on the catalytic performance, precise regulation on the catalyst structure holds great promise to bridge the activity gap between NPMCs and Pt-based benchmarks. In this minireview, we aim to provide an overview of recent progress in the structural regulation on NPMCs towards improved performance. The four typical categories of NPMCs, i.e., metal-free carbon-based materials, metal compounds, metal encapsulated in graphitic layer and atomically dispersed metal-nitrogen-carbon materials, are firstly introduced, where catalytic active sites and catalytic mechanism are highlighted. Subsequently, we summarize the representative structural regulation from a nanoscale to an atomic scale including hierarchically porous structure regulation, interface engineering, defect engineering and atomic pair construction. Special emphasis is placed on the elucidation of the catalytic structure-performance relationship. The origins of activity improvements from these structural regulations are discussed in terms of accelerated mass transfer, increased accessible active sites, tailored electronic states, and synergetic effect between multi-components. Finally, the challenges and opportunities are discussed.

Theoretical simulations of electrocatalysis are vital for understanding the mechanism of the electrochemical process at the atomic level. It can help to reveal the in-situ structures of electrode surfaces and establish the microscopic mechanism of electrocatalysis, thereby solving the problems such as electrode oxidation and corrosion. However, there are still many problems in the theoretical electrochemical simulations, including the solvation effects, the electric double layer, and the structural transformation of electrodes. Here we review recent advances of theoretical methods in electrochemical modeling, in particular, the double reference approach, the periodic continuum solvation model based on the modified Poisson-Boltzmann equation (CM-MPB), and the stochastic surface walking method based on the machine learning potential energy surface (SSW-NN). The case studies of oxygen reduction reaction by using CM-MPB and SSW-NN are presented.

Nickel(Ni)-rich layered oxide has been regarded as one of the most important cathode materials for the lithium-ion batteries because of its low cost and high energy density. However, the concerns in safety and durability of this compound are still challenging for its further development. On this account, the in-depth understanding in the structural factors determining its capacity attenuation is essential. In this review, we summarize the recent advances on the degradation mechanisms of Ni-rich layered oxide cathode. Progresses in the structure evolution of Ni-rich oxide are carefully combed in terms of inner evolution, surface evolution, and the property under thermal condition, while the state-of-the-art modification strategies are also introduced. Finally, we provide our perspective on the future directions for investigating the degradation of Ni-rich oxide cathode.

Metal-ion batteries have changed our quotidian lives. The research on the electrode materials for metal-ion battery is the key to improve the performance of the battery. Therefore, understanding the structure-performance relationship of the electrode materials can help to improve the energy density and power density of the materials. Magnetic resonance, including nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR), has been continuously improved during the past three decades, and has gradually become one of the important technologies to study the structure-performance relationship of electrode materials. This paper summarizes the progress of magnetic resonance research from our group on several interesting electrode materials and demonstrates the important role of NMR and EPR in the study of electrode materials. This article will help to grasp the important value of magnetic resonance technology for battery research, which will promote the further development of advance magnetic resonance technology.

Tin (Sn)-based materials have emerged as promising electrocatalysts for selective reduction of CO2 to formate, but their overall performances are still limited by electrode structures which govern the accessibility to active sites, the electron transfer kinetics, and the catalytic stability. In this study, the heterostructured Sn/SnO2 nanoparticles dispersed by N-doped carbon layer networks (Sn/SnO2@NC) were synthesized by a melt-recrystallization method taking the low melting point of Sn (m.p. 232^oC). The N-doped carbon layer networks derived from polydopamine could attract more electrons on the electrocatalyst, serve as conductive agents and protect the ultrafine nanoparticles from agglomeration and dissolution. The Sn/SnO2@NC electrode exhibited the greatly enhanced performance for CO2 reduction to formate in CO2-saturated 0.5 mol·L^-1 aqueous NaHCO3 solution, showing a selectivity of 83% at only -0.9 V vs. RHE with a sustained current density of 17 mA·cm^-2 for extended periods. By coupling the catalytic electrode with a commercially available RuO2 catalyst as the anode, the long-term CO2/H2O splitting has been achieved. Furthermore, a rechargeable aqueous Zn-CO2 battery with Sn/SnO2@NC as the cathode and Zn foil as the anode was constructed. It could output electric energy with an open circuit voltage of 1.35 V and a peak power density of 0.9 mW·cm^-2.

《电化学》（Journal of Electrochemistry，简称J. Electrochem.）1995年由田昭武院士、查全性院士和吴浩青院士等创办，为中国化学会电化学专业委员会会刊，是中国第一个、也是唯一的融基础理论研究与技术应用为一体的电化学专业学术期刊，由中国科学技术协会主管、中国化学会和厦门大学共同主办，2022年变更为月刊，向国内外公开发行。《电化学》旨在及时反映我国电化学领域的最新科研成果和动态，促进国内、国际的学术交流。《电化学》遵循国际通行的办刊惯例，实行主编、副主编负责制，所有刊出稿件均必须经过同行评议。

《电化学》自创刊以来，已分别被北京大学图书馆、中国科学院和中国科技信息研究所遴选为“中国核心期刊”，被CA、JST、CNKI、CSCD等国内外重要数据库收录，曾获《中国知识资源总库》精品期刊、华东地区优秀期刊等奖项。

竭诚欢迎广大学术界、产业界科技工作者踊跃投稿和订阅，为本刊献策建议。