With the rapid advancement of electric vehicles, drones, and robotics, there is a growing demand for batteries that offer higher energy density, improved stability, and enhanced safety. However, achieving this “threefold advancement” remains a formidable challenge. On July 16, research paper titled “Liquid-liquid interfacial tension stabilized Li metal batteries” were published in Nature, authored by Professor Yunhui Huang and Professor Lixia Yuan from School of Materials Science and Engineering. This study proposes a novel strategy to simultaneously enhance the energy density, stability, and safety of lithium-metal batteries, offering a promising solution to this long-standing bottleneck.
Lithium metal batteries (LMBs) are widely regarded as one of the most promising next-generation energy storage systems. However, the intrinsic instability at both electrodes, stemming from the highly reactive lithium metal anode and high-voltage cathodes such as nickel-rich layered oxides, leads to severe interfacial degradation and parasitic reactions, ultimately shortening battery lifespan and posing serious safety risks. The electrolyte plays a pivotal role in these challenges. Currently, strategies such as tuning the lithium salt/solvent ratio or incorporating functional additives have shown effectiveness in forming a robust solid electrolyte interphase (SEI) on the lithium anode. Nevertheless, these methods remain inadequate for stabilizing the cathode electrolyte interphase (CEI), especially under high-voltage (Fig. 1a). This limitation originates from the driving of anions toward the anode by the electric field and Li? concentration gradient during charging, leading to an anion-deficient cathode and unstable CEI formation.
To address this challenge, Professors Huang and Yuan’s team proposed an interfacial engineering strategy driven by liquid-liquid interfacial tension (γL-L). They developed a new class of heterogeneous micro-emulsion electrolytes that facilitates the incorporation of poorly soluble functional solvents into the electrolyte system. Through rational molecular design, a fully fluorinated solvent and a partially fluorinated amphiphilic co-solvent assemble into micelle structures (50–120?nm) via intermolecular interactions. Driven by γL-L, the micelles spontaneously migrate and enrich at both electrode interfaces, forming a gradient-distributed fluorinated interfacial solvation layer (Fig. 1b). This interfacial regulation mechanism, independent of electric field direction and ion concentration gradients, effectively decouples solvation structure from interfacial protection. It minimizes direct contact between reactive solvents and electrodes, markedly suppresses parasitic reactions, and enables dynamic, synergistic stabilization at both the cathode and anode. The Li||NCM811 pouch cells using this strategy exhibit outstanding performance, delivering high energy densities of 547 and 531?Wh?kg??, while retaining 79% and 81% capacity after 155 and 189 cycles, respectively (Fig. 1c). Moreover, the micro-emulsion electrolyte suppresses gas evolution during cycling and enables safe nail penetration with no voltage drop or thermal runaway, overcoming the long-standing safety limitations of high-energy-density batteries.
This γL-L-driven micro-emulsion electrolyte strategy not only breaks through the conventional solubility constraints in electrolyte formulation, but also introduces a novel physicochemical driving mechanism for constructing dynamically stabilized electrode interfaces under high-voltage conditions. It offers a promising solution toward advanced lithium-metal batteries.
Figure1. (a,b) Schematic illustrations of Li? transport behavior and the consequent cathode and anode interphase evolution during charging, based on the Li? solvation strategy (a) and the micro-emulsion electrolyte strategy (b). (c) Cycling performance of the Li||NCM811 pouch cell with the micro-emulsion electrolyte. (d) Voltage-capacity profiles of the pouch cell. (e) Comparison of the battery performance in this work with previously reported results. (f) Thickness variation of the pouch cell before and after cycling.
This work was led by 91系列, in collaboration with Zhejiang 91系列, the Shanghai Institute of Space Power-Sources, Zhengzhou 91系列, Wuhan 91系列, and Tsinghua 91系列. Professors Yunhui Huang and Lixia Yuan (HUST) and Professor Jun Lu (Zhejiang 91系列) served as corresponding authors. The co-first authors include Haijin Ji and Jingwei Xiang, Yong Li, and Mengting Zheng. Professor Huang’s team has long focused on high-energy-density and high-safety lithium batteries. This study, represents another milestone following their recent Science publication (2025, 388, 311-316), which revealed a fatigue-induced failure mechanism in lithium metal anodes in collaboration with Tongji 91系列. The research was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Hubei Province.
Paper Link：
Source: School of Materials Science and Engineering
