Stress-homogenized and solvation-regulated biomass hydrogel inducing Zn (101) epitaxial growth for ultra-stable anodes

Abstract

Crystallographic orientation and interfacial integrity dictate the reversibility of aqueous zinc-ion batteries at high current densities. To mitigate unstable growth, weak interactions, and uneven stress on the (002) and (100) planes, mechanically confining deposition to the robust (101) facet is vital, as its strong adsorption and rapid charge transfer prevent dendrite-induced failure at high cumulative capacity. Herein, we designed a degradable, mechanically tough, and carboxyl-rich biomass hydrogel to induce sustained Zn (101) epitaxial growth. It is shown that abundant carboxyl groups reconstruct the Zn2+ solvation sheath, suppressing free water activity and selectively shielding reactive (002) and (100) facets via competitive occupation, thereby thermodynamically directing (101) nucleation. Simultaneously, the cross-linked cellulose network delivers high toughness and a high elastic modulus, dissipating interfacial stress to preserve structural integrity against volume fluctuations. This dual regulation lowers the desolvation barrier, homogenizes ion flux, and physically suppresses dendrites, enabling dense (101)-textured deposition. Consequently, symmetric cells achieve an exceptional cumulative capacity of 6000 mAh cm−2 at 5 mA cm−2/5 mAh cm−2, while Zn//Cu cells maintain 99.31% coulombic efficiency over 2000 cycles. This work establishes a precise mechano-chemical strategy for crystallographic regulation toward ultra-stable zinc anodes.