Toward thin and stable anodes for practical lithium metal batteries: A review, strategies, and perspectives

The lithium metal battery (LMB) is a promising energy storage platform with a distinctively high energy density in theory, outperforming even those of conventional Li-ion batteries. In practice, however, the actual achievable energy density of LMBs is significantly limited due to the Li metal anode (LMA) being too thick (50–250 μm), and there are difficulties with expanding the highly reactive Li metal into large-format cells due to safety concerns. Therefore, the recent focus of LMB research is headed toward the development of a thin and stable LMA. However, as the thickness of Li anode decreases (≤20 μm) and the absolute size of the battery cell increases, interfacial reactions on the Li surface become more active, potentially leading to fatal thermal runaway. In this regard, there is still much demand for the development of novel manufacturing technologies to overcome this issue and produce thin and stable Li metal. Considering these things, in this review, we initially examine the fundamentals regarding the deployment of LMAs using a number of essential metrics. Then, we introduce recent strategies employed for designing thin and stable Li anodes including host matrix architecturing, interface stabilization, and other advanced modifications. Finally, we propose future directions for the realization of practical LMBs and their potential applications in various battery systems, encompassing Na, K, and Zn-based batteries. We anticipate that ultra-thin and ultra-stable metal anodes would find widespread utilization in secondary battery applications with high-power requirements.