Biopolymer CMC‐Derived Carbon Interfaces on Zn Anode for Green and Sustainable Zinc‐Ion Batteries

ABSTRACT Aqueous zinc‐ion batteries (ZIBs) are emerging as promising contenders for large‐scale energy storage owing to their intrinsic safety, cost‐effectiveness, and environmental sustainability. However, their practical application remains constrained by persistent issues at the Zn metal anode, including dendritic growth, interfacial passivation, and poor cycling stability. This study introduced a novel biopolymer‐based interfacial engineering strategy utilizing carboxymethyl cellulose (CMC), a zincophilic, water‐soluble, and sustainable biopolymer. A uniform CMC coating is applied via a scalable spray‐coating process and subsequently converted into a conductive carbonaceous interlayer through laser‐assisted carbonization, yielding a functional c‐CMC/Zn anode. This layer effectively suppresses dendrite formation, enhances Zn 2+ ion transport, and improves the overall electrochemical stability of the Zn anode. Symmetric cell tests demonstrate exceptional cycling performance, with stable operation exceeding 3600 h at 2.0 mA cm −2 and an areal capacity of 2.0 mAh cm −2 . When integrated into full‐cell architectures with V 2 O 5 cathodes, the c‐CMC/Zn║V 2 O 5 device achieves a high specific capacity of 319 mAh g −1 at 0.2 A g −1 and retains 77% of its capacity over 1000 cycles at 1.0 A g −1 . This work underscores the potential of laser‐carbonised biopolymer coatings as a versatile and scalable solution to the longstanding challenges of Zn anode instability in aqueous ZIB systems.