Recently, a collaborative research team comprising the German Helmholtz Institute Münster (HI-Münster), the MEET Battery Research Center (University of Münster), and Taiwan Tech’s NanoElectrochemistry Laboratory has achieved a significant breakthrough in lithium metal battery (LMBs) technology. By incorporating CHEMFISH’s high-performance electrolyte additive, lithium bis(oxalato)borate (LiPO₂F₂), the team markedly enhanced the interfacial stability and cycling performance of lithium metal batteries.

https://pubs.acs.org/doi/10.1021/acs.jpcc.0c09771?goto=supporting-info

Lithium metal batteries, with their high specific capacity and low redox potential, are regarded as strong contenders for next-generation high-energy-density battery technology. However, practical applications have been hindered by challenges such as “dead lithium” formation, uneven lithium deposition, and suboptimal solid electrolyte interphase (SEI) layers, which severely impact long-term performance and safety.

In this study, the research team investigated the effects of film-forming electrolyte additives (FEC and LiPO₂F₂) on improving lithium metal battery performance. Various battery configurations were employed, including Li||Li symmetric cells, Li||Cu cells, Cu||NMC cells, and NMC||Li full cells, to systematically evaluate the electrochemical performance of different active materials and electrolyte formulations.

Notably, the key additive LiPO₂F₂ used in the study was supplied by CHEMFISH. Its unique chemical properties were crucial to the study’s success. Solid-state ⁷Li NMR and in-situ optical microscope (OM) analyses revealed that when LiPO₂F₂ and FEC from CHEMFISH were added to the electrolyte together, they significantly reduced “dead lithium” formation and made lithium deposition more uniform. This optimized electrolyte formulation shows great potential for practical applications.

The research team also monitored anion concentration distribution using ¹⁹F 1D MRI technology and found that the electrolyte with CHEMFISH’s LiPO₂F₂ showed improved anion concentration depletion at the cathode side. This indicates that the additive effectively influenced electrode kinetics and played a positive role in suppressing lithium dendrite growth. Quantitative assessment of “dead lithium” content further confirmed that the electrolyte formulation with CHEMFISH products had a “dead lithium” fraction as low as 2.7%, significantly lower than other electrolyte formulations, and also had a relatively low fraction of lithium consumed during SEI formation.

XPS spectroscopy results showed that after using the electrolyte with CHEMFISH’s LiPO₂F₂, the LiF peak intensity in the SEI layer increased, directly indicating a significant improvement in SEI layer performance. Moreover, in different battery configurations, the electrolyte with CHEMFISH products was found to form thinner and more effective SEI films, greatly enhancing battery cycling stability and Coulombic efficiency.

This study fully demonstrates the excellent performance of CHEMFISH’s LiPO₂F₂ in the field of lithium metal batteries, taking a solid step toward the practical application and commercialization of lithium metal batteries. In the future, as related research continues to deepen, CHEMFISH is expected to play a key role in the new energy field and contribute to more innovative achievements.