Announcements

Dr. Delyana Marinova is one of the authors of the Title Story Article “Effect of the Peri-Annulated Dichalcogenide Bridge on the Bipolar Character of Naphthalimide Derivatives Used as Organic Electrode Materials” published in Materials (ISSN: 1996-1944).

Author Introduction

Dr. Delyana Marinova completed her PhD in the IR/Raman spectroscopic characterization of alkali transition metal polyanion compounds at the Institute of General and Inorganic Chemistry, which is part of the Bulgarian Academy of Sciences in Bulgaria. Her main research interests concern cathode materials for non-aqueous batteries with various electrolytes, including alkali transition metal sulfates and oxides, as well as organic compounds. Dr. Marinova has over 20 years of experience in the field of materials chemistry. Over the past decade, her electrochemical experiments have focused on studying cycling voltammetry and galvanostatic cyclic testing with different electrolytes for post-lithium-ion batteries. Her current research activities are focused on studying redox reactions in organic electrode materials with a naphthalimide core (peri-annulated naphthalimide derivatives) with bipolar characteristics.

Based on positive evaluations by reviewers and academic editors of Dr. Marinova group’s article, we have selected it as the Title Story for display on the Materials website.

“Effect of the Peri-Annulated Dichalcogenide Bridge on the Bipolar Character of Naphthalimide Derivatives Used as Organic Electrode Materials”
by Delyana Marinova, Lyuben Borislavov, Silva Stanchovska, Konstantin Konstantinov, Monika Mutovska, Stanimir Stoyanov, Yulian Zagranyarski, Yanislav Danchovski, Hristo Rasheev, Alia Tadjer et al.
Materials 2025, 18(9), 2066; https://doi.org/10.3390/ma18092066

The following is an interview with Dr. Delyana Marinova:

1. Congratulations on your published paper. Could you please briefly introduce the main research content of the paper?

Materials chemistry is a highly active area of research. There are many challenges in this scientific field, but the reversible transfer of electrons from one compound to another has always been of interest as a property of materials.

Oxidation–reduction reactions are the basis of energy conversion processes in living and non-living matter. In the inorganic world, reversible intercalation is the basic operating principle of lithium-ion batteries, which are a significant branch of energy storage today. In contrast to inorganic compounds, organic compounds have several advantages during redox reactions: diverse composition, easy modeling of the architecture, plasticity in terms of structural stresses, and, finally, a wide variety of natural resources necessary for their synthesis. The paper is part of complex fundamental research with a combinatorial approach between the synthesis of peri-substituted dichalcogen naphthalimides (NI) and the study of the reversibility of their redox reactions towards the alkali ions Li⁺ and Na⁺.

The architecture of selected compounds facilitates the progressive variation in the chalcogenide atoms in the bridge from S to Se and Te, and consequently, the effect of chalcogenides with decreasing electronegativity on the ability of NI derivatives to participate in both oxidation and reduction reactions can be precisely evaluated. All compounds contain chlorine atoms at positions 3 and 6, and an octyl chain. The redox properties of NI derivatives are monitored by using them as electrodes in lithium-ion cells with an electrolyte based on ionic liquids. The experimental findings are rationalized in the framework of DFT calculations. To improve the electronic conductivity of NIs, composites with rGO are also synthesized. The morphology and homogeneity of the resulting composites were investigated by scanning electron microscopy and Raman spectroscopy. The redox reactions at SCl8, SeCl8, and TeCl8 are monitored by means of CV experiments and galvanostatic tests. In general, the studied NI derivatives are reduced and oxidized in broad potential windows, between 1.0 V and 4.6 V, and 1.0 V and 4.3 V, respectively.

In conclusion, the oxidation of NI derivatives takes place above 3.9 V with the active participation of the chalcogenide bridge: the lower the electronegativity of the chalcogenide atoms, the higher the oxidation potential. TFSI⁻ counter-ions from the electrolyte provide charge compensation during the oxidation of NI derivatives. Compared to oxidation, NI derivatives are reduced stepwise below 2.0 V with a total of four Li⁺. The first reduction step (two Li) is accomplished with the participation mainly of the chalcogenide bridge, while during the next step of reduction, the imide fragment and naphthalene unit have an equal contribution to the charge reallocation. NI derivatives display satisfactory storage performance when used as organic electrodes in lithium half-cells. The comparison reveals that the SeCl8/rGO composite outperforms the SCl8/rGO and TeCl8/rGO analogues.

The favorable electrochemical properties could serve as a basis for identifying more suitable electrolyte compositions, thereby facilitating the enhancement of storage efficiency.

2. What are the key takeaways you hope readers will gain from your paper?

Several highlights of the topic of the publication can be summarized:

• The entire group of studied naphthalimide derivatives with a chalcogenide bridge can be very successfully developed as organic electrode materials with high efficiency;
• We chose a peri-dichalcogenide bridge, annulated to a naphthalimide core, as a bipolar redox molecular architecture;
• The redox properties of naphthalimide derivatives are observed by using them as electrodes in lithium-ion cells with an electrolyte based on ionic liquids;
• In order to improve the electronic conductivity, composites were made in reduced graphene oxide;
• Among different chalcogenide-derived compounds, the best performance in terms of cycling stability and rate capability is observed for the composites of Se-containing NIs and rGO.

3. How has your experience been publishing with Materials?

In total, all of the article’s authors have published 17 articles in the journal Materials over the last few years. Our colleagues from the Institute of General and Inorganic Chemistry have successfully completed two Special Issues of Materials as Guest Editors: “Size-Dependent Effects in Materials for Environmental Protection and Energy Applications” (1st and 2nd editions), comprising a total of 34 scientific publications. They are currently preparing a third Special Issue on this topic.

The fast publication process, from submission to online publication, is highly valued, of course, without compromising the quality of the review process. The journal offers many opportunities to promote individual articles and scientific teams, which is valuable in helping scientists spread their experience and knowledge.

The “Share and Cite” and “Article Metrics” Sections at the end of the website with scientific publications are also very favorable and useful. Last but not least, I have increasingly come across exhibition stands of the MDPI Publishing House at various scientific forums, conferences, and congresses in recent years. Colleagues there are interested in scientists’ opinions about the publishing process and take them into account.

4. How do you think open access publishing impacts authors?

Open access to publications greatly influences the dissemination of science, allowing every scientist in the world to familiarize themselves with proposed research. This gives researchers the opportunity to study issues of global importance, as well as create international contacts and learn from each other. The only drawback is that some research teams are unable to pay the open access fee due to differences in the economic development of individual countries.

In this regard, MDPI's policy of offering vouchers for reviewing publications and various discounts for guest editors, invitation for publishing in Special Editions, etc., is very beneficial, as it enables more scientists to share their research.