Uneven lithium intercalation and plating in graphite anodes severely affect the capacity decay and lifetime of lithium-ion batteries (LIBs). Visual and quantitative detection on the amount, distribution, and morphology of active lithium in/upon the graphite anodes is important for analyzing the performance and failure of anodes. Here, we design a novel solid-state fluorescence probe, TPECatechol, for graphite anodes. TPECatechol has a dual responsiveness to graphite anodes: a SWITCH of fluorescence wavelength and intensity when meeting active lithium or a complete QUENCH when touching graphite. Based on this, TPECatechol realized not only the visual observation of the nonuniform distribution of lithium intercalation and morphology of lithium plating but also a quantitative measurement of state of charge (SOC) of graphite anodes based on the different fluorescence intensities. The solid-state fluorescence imaging can reflect the actual condition of cycled anodes from real pouch batteries and provide a valid experimental means for understanding the electrochemical processes of LIBs.

石墨负极中不均匀的锂嵌入和电镀严重影响锂离子电池 (LIB) 的容量衰减和寿命。对石墨负极中/上方活性锂的数量、分布和形态进行目测和定量检测，对于分析负极的性能和失效具有重要意义。在这里，我们设计了一种用于石墨阳极的新型固态荧光探针 TPECatechol。TPECatechol 对石墨阳极具有双重响应：遇到活性锂时荧光波长和强度的切换或接触石墨时的完全猝灭。基于此，TPECatechol不仅实现了锂嵌入的非均匀分布和锂电镀形态的视觉观察，还实现了基于不同荧光强度的石墨负极荷电状态（SOC）的定量测​​量。固态荧光成像可以反映真实软包电池循环负极的实际情况，为理解锂离子电池的电化学过程提供有效的实验手段。