Addressing interfacial challenges in lithium metal batteries: A multi-pronged approach with 2-FBSA

As the most widely used energy storage device, lithium-ion batteries (LIBs) with graphite as the negative    electrode have already approached the theoretical limit of energy density, which cannot provide enough energy density required in electric vehicles in the pursuit of high driving range. Li metal, with an ultrahigh theoretical capacity (3860 mAh g⁻¹) and the lowest redox potential (−3.04 V vs. standard hydrogen electrode), is regarded as the “holy grail”of the next-generation negative electrode material.  As well known, the commercial electrolyte formulae with LiPF₆ as solute and organic carbonate as solvent have been widely used in the battery industry for several decades. However, carbonate solvents are tend to decompose on the surface of highly reductive Li metal anode and form loose solid electrolyte interphase (SEI) rich in organic Li salts. This phenomenon induces Li dendrite growth and the continuous electrolyte decomposition, greatly limiting the practical application of Li metal batteries

The team published their research in Nano Research on November 28, 2025.

The authors report an additive 2-fluorobenzenesulfonamide (2-FBSA), which possesses three major functional groups that can regulate both electrode interfaces effectively. Comprehensive characterization analyses reveal that the solvation clusters formed by 2-FBSA molecules exhibit a lower de-solvation energy barrier, thereby accelerating Li⁺ transport kinetics. Further comprehensive characterization analyses are carried out to study the working mechanism of 2-FBSA additive. Furthermore, the introduction of 2-FBSA enhances the solvation degree of ions and free solvent molecules, and the newly formed solvation clusters were more inclined   to adsorb on the Li electrode surface, preferentially participating in the further interface construction. Thus, the C-F, amino, and sulfonyl functional groups existing in 2-FBSA will be decomposed preferentially to form SEI rich in F, N, and S inorganic Li salts on the electrode surface. As excellent Li⁺ conductors and electronic insulators, these inorganic Li salts can homogenize the transport behavior of Li⁺. At the same time, the high Young’ s modulus of inorganic Li salts enables them to resist stress changes caused by volume expansion    during electrode cycling. This effectively alleviates both interfacial side reactions and uncontrollable Li dendrite growth affecting the Li metal anode, thereby improving the mechanical and     electrochemical performance of the SEI and ensuring stable battery cycling. In addition, ROSO₂Li is produced on positive particles owing to the decomposition of sulfonyl group, which has been proven to be a good passivation component, and effective in maintaining the stability of the positive electrode interface. Therefore, with assistance of optimal dosage additive, Li-Li symmetric batteries prolong the lifetime (2400 h) at 0.5 mA cm^-2, more than twice that of additive free cells. And the assembled Li-LiFePO₄ full cells have also been tested, demonstrating outstanding capacity retention (72%) after 400 cycles at 1 C, significantly higher than that without additive participation.

This work was supported by the National Natural Science Foundation of China (Nos. 22279070 (L. W.) and U21A20170 (X. H.)), the Ministry of Science and Technology of China (2019YFA0705703 (L. W.)), the Beijing Natural   Science   Foundation (No. L242005 (X. H.))   and   the “Explorer 100” cluster system of Tsinghua National Laboratory for Information Science and Technology.

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.