image: (a) Schematic d-band model and (b) energy band diagrams. (c) HER volcano pot. (d) Schematic illustration of this work.
Credit: ©Science China Press
In the global race for sustainable energy storage solutions, aqueous zinc-ion batteries have long been considered a highly promising candidate due to their inherent safety, low cost, and environmental friendliness. However, the fundamental challenges faced by zinc metal anodes in practical applications—uncontrollable dendrite growth, vigorous hydrogen evolution side reactions, and the deposition of harmful by-products—act as a formidable barrier, hindering their path toward large-scale commercialization. These challenges are interconnected, forming a vicious cycle: the hydrogen evolution reaction leads to a localized increase in pH at the electrode interface and continuous corrosion of zinc, which in turn induces the formation of inert by-products; dendrites can pierce the separator, causing battery short circuits. Traditional modification strategies have mostly focused on constructing physical protective layers or electrolyte engineering, often addressing the symptoms rather than the root cause.
Recently, a groundbreaking study has brought a completely new solution to this dilemma. An interdisciplinary research team boldly applied the core theory from catalytic chemistry—the "d-band center modulation" strategy—to the interfacial design of aqueous zinc batteries. By introducing a simple organic small-molecule additive, they achieved precise "reprogramming" of the reaction kinetics on the zinc electrode surface, suppressing side reactions at their electronic-structure source and significantly enhancing the battery's cycle life and safety.
In catalysis science, the position of a catalyst's d-band center is a key parameter describing its surface electronic state, directly determining the adsorption strength of reactant molecules on the catalyst surface, thereby influencing the reaction pathway and rate. The research team keenly realized that the hydrogen evolution reaction on the zinc metal anode surface is essentially an electrocatalytic process. Could they draw inspiration from catalysis theory to weaken the adsorption of hydrogen intermediates (H*) by modulating the electronic structure of the zinc surface, thus fundamentally "applying the brakes" to the hydrogen evolution reaction?
Based on this concept, the team systematically screened various organic molecules and ultimately found that oxalic acid (OA) is an ideal "interface modulator." Combining first-principles calculations, the researchers revealed its mechanism of action: oxalic acid molecules can specifically adsorb onto the zinc anode surface. This adsorption is not simple physical coverage but triggers a profound change in the electronic structure of the surface zinc atoms—shifting their d-band center significantly from -6.896 eV down to -7.062 eV. The downshift of the d-band center means the weakened ability of the zinc surface electrons to adsorb hydrogen intermediates. Computational simulations visually show that the adsorption energy of hydrogen intermediates on the modulated zinc surface decreases, making their desorption easier, thereby greatly reducing the thermodynamic driving force and kinetic rate of the hydrogen evolution reaction.
The utility of oxalic acid goes beyond this. The research team further discovered that it also plays the role of a "solvation structure editor" within the electrolyte bulk. Using various methods such as Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and molecular dynamics simulations, it was confirmed that oxalic acid molecules can partially replace water molecules to enter the primary solvation sheath of zinc ions. This reconstruction produces a dual positive effect: First, it reduces the number of active water molecules directly coordinated with zinc ions, lowering the possibility of water participating in side reactions. Second, it weakens the interaction between sulfate anions and zinc ions, suppressing the interfacial deposition of by-products such as zinc hydroxide sulfate at the source. Therefore, the oxalic acid additive achieves synergistic effects that kill multiple birds with one stone: it "calms" the electrode surface electronically to suppress hydrogen evolution and "purifies" the reaction interface in the solution phase to reduce by-products. This two-pronged strategy creates a stable and uniform deposition/dissolution environment for zinc metal.
Performance test results fully validate the outstanding effectiveness of this strategy. In full-cell tests, the Zn||I2 full cell paired with an iodine cathode demonstrated astonishing longevity, maintaining 92.8% capacity retention after 10,000 cycles. Even more encouraging, the team fabricated ampere-hour-level pouch cells, which still exhibited stable cycling performance under bending conditions, showcasing their potential for practical application.
The authors of this study stated: "This work is a successful exploration of interdisciplinary cross-fertilization. It enlightens us that solving stubborn problems in the energy storage field sometimes requires drawing wisdom from adjacent disciplines. Catalysis theory provides us with a new lens through which to understand and design electrode/electrolyte interfaces."
This research not only provides an efficient, low-cost additive solution for developing high-performance aqueous zinc batteries but, more importantly, it pioneers a new paradigm for designing metal anodes through precise modulation of electrode surface electronic structure. This "catalysis-inspired" strategy holds promise for extension to other highly reactive metal anode systems facing similar interfacial challenges, such as lithium, sodium, and aluminum metal batteries, injecting new developmental momentum into next-generation high-performance, high-safety battery technologies. As global demand for sustainable energy storage grows increasingly urgent, such interdisciplinary research that starts from fundamental theoretical innovation and directly targets core industrial application problems is becoming a key force driving technological revolution.