近日，西湖大学王建辉团队研究了从电池到原子水平：了解99%库仑效率和450 Wh kg^–1无阳极软包电池的退化。该项研究成果发表在2025年10月28日出版的《美国化学会志》上。

无阳极锂金属电池（AFLMBs）理论上可实现超过500 Wh kg^–1的超高能量密度，然而现有研究主要集中于能量密度低于350 Wh kg^–1的体系，这类电池既缺乏相较于商用锂离子电池的优势，也难以揭示高能量密度下电池衰退的机理。

研究组成功研制出安时级、450 Wh kg^–1能量密度的无阳极锂金属电池，其库仑效率超过99%，并通过电池、电极及原子尺度的联合分析揭示了其衰退机制。在高能量密度条件下（正极面容量5.6 mAh cm^–2，电解液用量2.0 g Ah^–1），电池性能衰减主要受非活性锂的主导作用。研究发现了“突然失效”与“渐进衰减”两种典型衰退模式：前者与脆性固态电解质界面（SEI）导致的“块菌状”死锂相关，后者则与柔性SEI交织的“蘑菇状”活性锂形成有关。

其中，渐进衰减模式因退化速度较慢且死锂量最少，展现出更优的循环寿命与安全性。此外，研究证实SEI的弹性变形相较于杨氏模量是稳定锂金属的更可靠参数。这些发现与既往低能量密度研究存在显著差异——在较低库仑效率和大量死锂存在时，低能量密度电池仍可循环多次，而该研究建立了更可靠的高能量密度电池“组成-结构-性能”失效关联机制，为开发实用化高能量密度无阳极锂金属电池提供了理论依据。

附：英文原文

Title: From Cell to Atomic Level: Understanding the Degradation in 99% Coulombic Efficiency and 450 Wh kg–1 Anode-Free Pouch Cells

Author: Lei Liu, Yuxuan Xiang, Jianhui Wang

Issue&Volume: October 28, 2025

Abstract: Anode-Free Lithium Metal Batteries (AFLMBs) promise ultrahigh energy densities beyond 500 Wh kg–1, yet prior work mainly studied on <350 Wh kg–1 AFLMBs, which lack advantages over commercial Li-ion batteries and mechanistic understanding of battery degradation at high-energy levels. Here, we developed Ah-level 450 Wh kg–1 AFLMBs with >99% Coulombic efficiency (CE) and examined their degradation across cell, electrode, and atomic dimensions. Under high-energy-density conditions (5.6 mAh cm–2 cathode, 2.0 g Ah–1 electrolyte), the battery degradation behavior is dictated by the dominant inactive lithium component. Two typical modes of “sudden death” and “gradual decay” are revealed, which are associated with “truffle-shaped” dead lithium caused by brittle solid electrolyte interphase (SEI) and “mushroom-shaped” active lithium interwoven with flexible SEI, respectively. The gradual-decay mode, with slower degradation and minimized dead lithium, exhibits a superior lifespan and safety. In addition, the SEI’s elastic deformation emerges as a more reliable parameter than Young’s modulus for lithium metal stabilization. These findings are different from previous lower-energy-density studies, wherein the batteries could run many cycles even under a relatively low CE and abundant dead lithium, thus establishing a more reliable composition–structure–performance correlation for battery failure and facilitating the development of high-energy-density practical AFLMBs.

DOI: 10.1021/jacs.5c09562

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c09562