Breaking performance limits of Zn anodes in aqueous batteries by tailoring anion and cation additives

A landmark study in Nano-Micro Letters led by Zhaoxu Mai, Gongzheng Yang and Chengxin Wang from Sun Yat-sen University overturns the long-held belief that a single (002)-textured Zn surface is enough to guarantee long-term stability. By introducing benzyltriethylammonium chloride (TEBAC) and then surgically removing its chloride counter-ion, the team creates an electrolyte that not only locks the (002) plane in place with an unprecedented 99.8 % relative texture coefficient but also eliminates pitting corrosion, delivering 9000 h (375 days) of dendrite-free cycling in coin and pouch cells at 1 mA cm^-2 / 1 mAh cm^-2 and 1 000 cycles at 10 A g^-1 in Zn||VO₂ full cells.

Why This Research Matters
• From Texture to Durability: Conventional wisdom holds that a highly (002)-textured Zn anode suppresses dendrites and hydrogen evolution. Yet, the authors first demonstrate that even a pristine (002) foil loses its texture after ~120 h in 2 M ZnSO₄, leading to random grain growth and early failure.
• Additive-Induced, Self-Reinforcing Texture: A mere 0.04 M TEBA⁺ selectively adsorbs on high-energy (100)/(101) planes, steering Zn²⁺ to lateral growth along the low-energy (002) plane. Commercial-grade Zn foils evolve from 29 % to 90.6 % (002) texture within 250 cycles—without any pre-treatment.
• Cl^--Free Paradigm: While TEBAC is vital for texture control, its Cl^- triggers severe pitting corrosion. Replacing Cl^- with SO₄^2- removes corrosion cells, slashes HER by 50 %, and extends symmetric-cell life 24-fold (3000 h → 9000 h).

Innovative Design and Mechanisms
• Scalable Electrodeposition: Using only Ti foil and Zn foil in a 1 M ZnSO₄ bath at 100 mA cm^-2, the team fabricates free-standing (002)-textured foils with millimeter-scale grains in 15 min—compatible with roll-to-roll production.
• Dynamic Texture Locking: In situ optical microscopy and chronoamperometry reveal that TEBA⁺ continuously re-adsorbs during plating/stripping, ensuring the (002) plane remains dominant even under 10 mA cm^-2 high-rate pulses.
• DFT-Guided Adsorption: Calculations show TEBA⁺ binds 0.97 eV weaker on (002) than on (100)/(101), aligning with Bravais’ law and rationalizing the observed lateral growth.

Applications and Future Outlook

With a 375-day coin-cell life and 1000-cycle pouch-cell endurance already demonstrated, the TEBA⁺-engineered electrolyte is now ready for technology transfer from lab to grid-scale storage. The team is collaborating with industry partners to upscale the 100 mA cm^-2 electrodeposition process to continuous foil production (>1 m min^-1), aiming for 100 µm-thick Zn electrodes that retain the 99.8 % (002) texture. Pilot-scale pouch cells (6 Ah) are being assembled to validate performance under dynamic temperature (-40 to 60 °C) and mechanical flexing conditions for electric-bus and marine micro-grid applications. Looking ahead, the researchers will integrate the electrolyte with solid-state polymeric separators and high-voltage MnO₂ cathodes to push cell voltage beyond 2.0 V while maintaining the same ultra-long cycle life. The dual-ion engineering concept—cation steering plus anion de-risking—is also being adapted for magnesium and aluminum anodes, promising a universal platform for next-generation, low-cost, high-energy-density aqueous batteries.