Recycling lithium from spent batteries is challenging because of problems with poor purity and contamination. Here, we propose a green and sustainable lithium recovery strategy for spent batteries containing LiFePO 4 , LiCoO 2 , and LiNi 0.5 Co 0.2 Mn 0.3 O 2 electrodes. Our proposed configuration of “lithium-rich electrode || LLZTO@LiTFSI+P3HT || LiOH” system achieves double-side and roll-to-roll recycling of lithium-containing electrode without destroying its integrity. The LiTFSI+P3HT-modified LLZTO membrane also solves the H + /Li + exchange problem and realizes a waterproof protection of bare LLZTO in the aqueous working environment. On the basis of these advantages, our system shows high Li selectivity (97%) and excellent Faradaic efficiency (≥97%), achieving high-purity (99%) LiOH along with the production of H 2 . The Li extraction processes for spent LiFePO 4 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , and LiCoO 2 batteries is shown to be economically feasible. Therefore, this study provides a previously unexplored technology with low energy consumption as well as high economic and environmental benefits to realize sustainable lithium recycling from spent batteries.

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Aqueous Zn-ion batteries are plagued by a short lifespan caused by localized dendrites. High-concentration electrolytes are favorable for dense Zn deposition but have poor performance in batteries with glass-fiber separators. In contrast, low-concentration electrolytes can wet the separators well, ensuring the migration of zinc ions, but the dendrites grow rapidly. In this work, we propose an electrolyte gradient strategy wherein a zinc-ion concentration gradient is established from the anode to the separator, ensuring that the separator keeps a good wettability in low-concentration areas and the zinc anode achieves dendrite-free deposition in a high-concentration area. By using this strategy in a common electrolyte, zinc sulfate, a Zn||Zn symmetric cell achieves 14 000 ultralong cycles (exceeding 8 months) at 5 mA cm −2 and 1 mAh cm −2 . When the current is further increased to 20 mA cm −2 , the symmetric cell could still run for over 10 000 cycles. Assembled Zn||NVO full cells also demonstrate prominent performance. At a high current of 16 mA cm −2 , the NVO cathode with high loading (8 mg cm −2 ) still has a capacity of 58% after 1200 cycles. Overall, the gradient electrolyte strategy provides a promising approach for practical long-life Zn anodes with the advantages of simple operation and low cost.

Garnet electrolytes, possessing high ionic conductivity (10−4–10−3 S cm−1 at room temperature) and excellent chemical/electrochemical compatibility with lithium metal, are expected to be used in solid‐state lithium metal batteries. However, the poor solid–solid interfacial contact between lithium and garnet leads to high interfacial resistance, reducing the battery power capability and cyclability. Garnet electrolytes are commonly believed to be intrinsically lithiophilic, and lithiophobic Li2CO3 on the garnet surface accounted for the poor interfacial contact. Here, it is proposed that the interfacial lithiophobicity/lithiophilicity of garnets (LLZO, LLZTO) can be transformed above a temperature of ≈380 °C. This transition mechanism is also suitable for other materials such as Li2CO3, Li2O, stainless steel, and Al2O3. By using this transition mechanism, uniform and even lithium can be strongly bonded no‐surface‐treated garnet electrolytes with various shapes. The Li–LLZTO interfacial resistance can be reduced to ≈3.6 Ω cm2 and sustainably withstood lithium extraction and insertion for up to 2000 h at 100 µA cm−2. This high‐temperature lithiophobicity/lithiophilicity transition mechanism can help improve the understanding of lithium–garnet interfaces and build practical lithium–garnet solid–solid interfaces.

The FeS 2 has abundant reserves and a high specific capacity (894 mAh g −1 ), commonly used to fabricate Li-FeS 2 primary batteries, like LiM x -FeS 2 thermal batteries (working at ≈500 °C). However, Li-FeS 2 batteries struggle to function as rechargeable batteries due to serious issues such as pulverization and polysulfide shuttling. Herein, highly reversible solid-state Li-FeS 2 batteries operating at 300 °C are designed. Molten salt-based FeS 2 slurry cathodes address the notorious electrode pulverization problem by encapsulating pulverized particles in time with e − and Li + flow conductors. In addition, the solid electrolyte LLZTO tube serves as a hard separator and fast Li + channel, effectively separating the molten electrodes to construct a liquid-solid-liquid structure instead of the solid-liquid-solid structure of LiM x -FeS 2 thermal batteries. Most importantly, these high-temperature Li-FeS 2 solid-state batteries achieve FeS 2 conversion to Li 2 S and Fe at discharge and further back to FeS 2 at charge, unlike room-temperature Li-FeS 2 batteries where FeS and S act as oxidation products. Therefore, these new-type Li-FeS 2 batteries have a lower operating temperature than Li-FeS 2 thermal batteries and perform highly reversible electrochemical reactions, which can be cycled stably up to 2000 times with a high specific capacity of ≈750 mAh g −1 in the prototype batteries.