With the rapid advancement of electric vehicles, energy storage systems, and consumer electronics, a demand for high-performance lithium-ion batteries (LIBs) is escalating. The electrolyte plays a pivotal role in affecting the battery performance, safety, and longevity. Liquid electrolytes, which are widely used in commercial LIBs, offer high ionic conductivity and ease of processing. However, solid electrolyte interphase (SEI) formed in liquid electrolyte systems degrades during repeated charge–discharge cycles, increasing impedance, reducing the Coulombic efficiency, and compromising cycling stability. In contrast, solid-state electrolytes, known for their potential to enhance battery safety, face some challenges such as lower ion conductivity, poor mechanical properties, and difficulties in maintaining stable electrode interfaces under operational conditions.The electrolyte-electrode interface, particularly at anode, is crucial for lithium battery performance. Lithium dendrite growth is a primary concern as it can cause short circuits and battery failure. In liquid electrolyte systems, dendrite formation is accelerated by uneven ion flow, SEI instability, and excessive current density. Solid-state electrolytes, while promising in terms of theoretical safety, also face some challenges, i.e., slower ion conductivity at room temperature and poor interface stability with lithium metal anodes. A better understanding of these differences is crucial for advancing electrolyte design.One of the key challenges for liquid electrolytes is to control SEI formation. The chemical composition and morphology of the SEI directly impact the battery performance. A thick or uneven SEI layer increases internal resistance and slows ion flow, thereby reducing the Coulombic efficiency and cycle stability. In solid-state systems, the solid-solid interface between the electrolyte and electrode material leads to a high interfacial resistance, restricting ion migration and affecting charge-discharge efficiency. Ion transport in solid-state electrolytes is also more uneven and slower, further compromising safety. While SEI formation in liquid electrolytes can suppress dendrite growth and promote uniform lithium deposition, solid-state electrolytes tend to exhibit a higher interfacial resistance, which accelerates dendrite growth and leads to short circuits. These distinct interface properties are the main cause of the performance gap between liquid and solid-state batteries.Optimizing interface stability and ion flow uniformity in both liquid and solid-state electrolytes is essential for improving battery technology. In this review, the characteristics of the anode interface in both systems are compared, with a focus on lithium dendrite growth mechanisms. Some factors like ion conductivity, electrode-electrolyte interactions, and interface stability that affect electrochemical performance are mentioned. This review also analyzes strategies to optimize electrolyte interface stability and ion flow uniformity in both liquid-state and solid-state systems. Electrolyte design strategies based on ion flow regulation to enhance ion conductivity, reduce interfacial resistance, and ensure more uniform ion distribution are proposed. These strategies include the development of advanced electrolyte materials, interface engineering to improve ion transport, and the use of hybrid systems that combine the advantages of both liquid and solid electrolytes.Summary and prospectsSolid-state and liquid-state electrolytes exhibit significant differences, particularly in ionic conductivity and interface stability. While liquid electrolytes with their higher fluidity can quickly respond to ion flow, they face some challenges such as flammability and side reactions at the interface, which compromise battery safety. Solid-state electrolytes with their theoretically higher safety have attracted significant attention, but their practical application is limited due to the problems such as bulk inhomogeneity leading to uneven ionic conductivity and unstable electrode interfaces. Moreover, the mechanical rigidity of solid materials results in poor interface contact and stress accumulation during cycling, which further degrades battery performance and reduces cycle life. Achieving uniform ion flow is crucial for the stable cycling and optimal performance of batteries. Optimizing the ion mobility between the electrolyte and electrode is essential for improving efficiency and extending cycle life, regardless of whether the electrolyte is solid or liquid. Design strategies based on ion flow regulation can enhance electrolyte ionic conductivity via optimizing microstructure, advancing interface engineering, and developing composite electrolyte systems. These strategies improve ion mobility, reduce interface impedance, and enhance the beneficial feedback of the interface, leading to better cycling performance and stability. In addition, the rapid growth of machine learning and big data technologies also presents a transformative opportunity for novel electrolyte materials development. Moving forward, as battery technology progresses, electrolyte optimization will focus on improving the ionic conductivity of the electrolytes themselves and optimizing the entire battery system. In commercial applications, reducing failure rates to minimal levels is essential where safety standards are extremely stringent. To meet this, enhancing the ion flow and interface stability of electrolytes will be crucial for developing high-safety, long-lifetime batteries. Moreover, integrating machine learning and big data into electrolyte optimization will drive breakthroughs in battery performance, supporting the commercialization of next-generation high-performance batteries.