Ineffective control of dendrite growth and side reactions on Zn anodessignificantly retards commercialization of aqueous Zn-ion batteries. Unlikeconventional interfacial modification strategies that are primarilyfocused on component optimization or microstructural tuning, herein, wepropose a crystallinity engineering strategy by developing highly crystallinecarbon nitride protective layers for Zn anodes through molten salttreatment. Interestingly, the highly ordered structure along with sufficientfunctional polar groups and pre-intercalated K⁺ endows the coating withhigh ionic conductivity, strong hydrophilicity, and accelerated ion diffusionkinetics. Theoretical calculations also confirm its enhanced Znadsorption capability compared to commonly reported carbon nitridewith amorphous or semi-crystalline structure and bare Zn. Benefitingfrom the aforementioned features, the as-synthesized protective layerenables a calendar lifespan of symmetric cells for 1100 h and outstandingstability of full cells with capacity retention of 91.5% after 1500 cycles. Thiswork proposes a new conceptual strategy for Zn anode protection.

There has been a significant scope toward the cutting-edge investigations in hierarchical carbon nanostructured electrodes originating from cellulosic materials, such as cellulose nanofibers, available from natural cellulose and bacterial cellulose. Elements of energy storage systems (ESSs) are typically established upon inorganic/metal mixtures, carbonaceous implications, and petroleum-derived hydrocarbon chemicals. However, these conventional substances may need help fulfilling the ever-increasing needs of ESSs. Nanocellulose has grown significantly as an impressive 1D element due to its natural availability, eco-friendliness, recyclability, structural identity, simple transformation, and dimensional durability. Here, in this review article, we have discussed the role and overview of cellulose-based hydrogels in ESSs. Additionally, the extraction sources and solvents used for dissolution have been discussed in detail. Finally, the properties (such as self-healing, transparency, strength and swelling behavior), and applications (such as flexible batteries, fuel cells, solar cells, flexible supercapacitors and carbon-based derived from cellulose) in energy storage devices and conclusion with existing challenges have been updated with recent findings.