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Organic electrode materials are promising for green and sustainable lithium‐ion batteries. However, the high solubility of organic materials in the liquid electrolyte results in the shuttle reaction and fast capacity decay. Herein, azo compounds are firstly applied in all‐solid‐state lithium batteries (ASSLB) to suppress the dissolution challenge. Due to the high compatibility of azobenzene (AB) based compounds to Li₃PS₄(LPS) solid electrolyte, the LPS solid electrolyte is used to prevent the dissolution and shuttle reaction of AB. To maintain the low interface resistance during the large volume change upon cycling, a carboxylate group is added into AB to provide 4‐(phenylazo) benzoic acid lithium salt (PBALS), which could bond with LPS solid electrolyte via the ionic bonding between oxygen in PBALS and lithium ion in LPS. The ionic bonding between the active material and solid electrolyte stabilizes the contact interface and enables the stable cycle life of PBALS in ASSLB.

The wide applications of rechargeable batteries require state‐of‐the‐art batteries that are sustainable (abundant resource), tolerant to high‐temperature operations, and excellent in delivering high capacity and long‐term cycling life. Due to the scarcity and uneven distribution of lithium, it is urgent to develop alternative rechargeable batteries. Herein, an organic compound, azobenzene‐4,4′‐dicarboxylic acid potassium salts (ADAPTS) is developed, with an azo group as the redox center for high performance potassium‐ion batteries (KIBs). The extended π‐conjugated structure in ADAPTS and surface reactions between ADAPTS and K‐ions enable the stable charge/discharge of K‐ion batteries even at high temperatures up to 60 °C. When operated at 50 °C, ADAPTS anode delivers a reversible capacity of 109 mAh g⁻¹at 1C for 400 cycles. A reversible capacity of 77 mAh g⁻¹is retained at 2C for 1000 cycles. At 60 °C, the ADAPTS‐based KIBs deliver a high capacity of 113 mAh g⁻¹with 81% capacity retention at 2C after 80 cycles. The exceptional electrochemical performance demonstrates that ADAPTS is a promising electrode material for high‐temperature KIBs.

Organic compounds are desirable alternatives for sustainable lithium‐ion battery electrodes. However, the electrochemical properties of state‐of‐the‐art organic electrodes are still worse than commercial inorganic counterparts. Here, a new chemistry is reported based on the electrochemical conversion of nitro compounds to azo compounds for high performance lithium‐ion batteries. 4‐Nitrobenzoic acid lithium salt (NBALS) is selected as a model nitro compound to systemically investigate the structure, lithiation/delithiation mechanism, and electrochemical performance of nitro compounds. NBALS delivers an initial capacity of 153 mAh g⁻¹at 0.5 C and retains a capacity of 131 mAh g⁻¹after 100 cycles. Detailed characterizations demonstrate that during initial electrochemical lithiation, the nitro group in crystalline NBALS is irreversibly reduced into an amorphous azo compound. Subsequently, the azo compound is reversibly lithiated/delithiated in the following charge/discharge cycles with high electrochemical performance. The lithiation/delithiation mechanism of azo compounds is also validated by directly using azo compounds as electrode materials, which exhibit similar electrochemical performance to nitro compounds, while having a much higher initial Coulombic efficiency. Therefore, this work proves that nitro compounds can be electrochemically converted to azo compounds for high performance lithium‐ion batteries.