Zinc metal anode in aqueous zinc-ion batteries (AZIBs) is considerably impeded by uncontrollable dendrite growth and intricately water-induced corrosion, leading to low Coulombic efficiency (CE) and limited lifespan. Herein, a...
The irregular and random electrodeposition of zinc has emerged as a non‐negligible barrier for deeply rechargeable aqueous zinc (Zn)‐ion batteries (AZIBs), yet traditional texture regulation of the Zn substrate cannot continuously induce uniform Zn deposition. Here, a Janus separator is constructed via parallelly grown graphene sheets modified with sulfonic cellulose on one side of the commercial glass fiber separator through the spin‐coating technique. The Janus separator can consistently regulate Zn growth toward a locked crystallographic orientation of Zn(002) texture to intercept dendrites. Furthermore, the separator can spontaneously repel SO42− and anchor H+ while allowing effective transport of Zn2+ to alleviate side reactions. Accordingly, the Zn symmetric cell harvests a long‐term lifespan over 1400 h at 10 mA cm−2/10 mAh cm−2 and endures stable cycling over 220 h even at a high depth of discharge (DOD) of 56%. The Zn/carbon nanotube (CNT)–MnO2 cell achieves an outstanding capacity retention of 95% at 1 A g−1 after 1900 cycles. Furthermore, the Zn/NH4V4O10 pouch cell with a Janus separator delivers an initial capacity of 178 mAh g−1 and a high capacity retention of 87.4% after 260 cycles. This work provides a continuous regulation approach to achieve crystallographic homogeneity of the Zn anode, which can be suitable for other metal batteries.
The
instability of Zn anode caused by severe dendrite growth and
side reactions has restricted the practical applications of aqueous
zinc-ion batteries (AZIBs). Herein, an enamel-like layer of nanohydroxyapatite
(Ca5(PO4)3(OH), nano-HAP) is constructed
on Zn anode to enhance its stability. Benefiting from the ion exchange
between Zn2+ and Ca2+, the adsorption for Zn2+ in enamel-like nano-HAP (E-nHAP) layer can effectively guide
Zn deposition, ensuring homogeneous Zn2+ flux and even
nucleation sites to suppress Zn dendrites. Meanwhile, the low pH of
acidic electrolyte can be regulated by slightly soluble nano-HAP,
restraining electrolyte corrosion and hydrogen evolution. Moreover,
the E-nHAP layer features high mechanical flexibility due to its enamel-like
organic–inorganic composite nanostructure. Hence, symmetric
cells assembled by E-nHAP@Zn show superior stability of long-term
cycling at different current densities (0.1, 0.5, 1, 5, and 10 mA
cm–2). The E-nHAP@Zn∥E-nHAP@Cu cell exhibits
an outstanding cycling life with high Coulombic efficiency of 99.8%
over 1000 cycles. Notably, the reversibility of full cell based on
CNT/MnO2 cathode can be effectively enhanced. This work
shows the potential of drawing inspiration from biological nanostructure
in nature to develop stable metal electrodes.
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