At the core of various energy storage devices and corrosion protection projects, zinc cathodes play
an indispensable role with their unique advantages. They are not only the “unsung heroes” of battery
anode materials but also the “loyal guardians” of metal defenses. In today's world, where safety and
cost-effectiveness are increasingly prioritized, the value of zinc cathodes is becoming increasingly evident.
Zinc's Deep Roots and Application Advantages in the Battery Field
Zinc has a long history and broad foundation as a battery anode material. Traditional zinc-manganese batteries,
alkaline zinc-manganese batteries, and the rapidly developing zinc-air batteries and zinc-nickel batteries in
recent years all rely on zinc as the core anode active material. Zinc's core advantages in battery systems are
evident in multiple aspects:
High safety: Zinc exhibits relatively stable chemical properties in conventional aqueous electrolytes, making it
less prone to violent reactions. Compared to some organic battery systems, it significantly reduces the risk of
thermal runaway and combustion/explosion, making it particularly suitable for portable devices, medical
instruments, and applications in special environments with stringent safety requirements.
Environmental friendliness: Zinc itself has low toxicity, and the majority of zinc-based battery systems use aqueous
or near-neutral electrolytes, avoiding the use of harmful organic solvents and heavy metals. This significantly
reduces the environmental burden associated with production, use, and subsequent recycling and disposal.
Resource and cost advantages: Zinc is abundant in the Earth's crust, with mature mining and smelting technologies,
resulting in raw material costs far lower than those of strategic resources like lithium and cobalt. This gives zinc-based
batteries significant price competitiveness in disposable batteries and certain rechargeable applications, facilitating
large-scale adoption and promotion.
Stable Operating Voltage: The zinc electrode reaction (Zn ⇌ Zn²⁺ + 2e⁻) provides a relatively stable discharge voltage
platform, particularly prominent in disposable batteries, ensuring stable operation of electrical devices.
High theoretical capacity: Zinc itself has a high mass-specific capacity (approximately 820 mAh/g) and volume-specific
capacity (approximately 5,855 mAh/cm³), making it possible to design high-energy-density batteries.
The key role of zinc cathodes in electrochemical corrosion protection
Zinc cathodes play a distinct yet equally important role in corrosion protection—sacrificial anodes (or cathodic protection).
The core principle lies in utilizing zinc's standard electrode potential, which is more negative than that of commonly used
metals like steel. When the two are electrically connected in an electrolyte (such as soil or seawater), zinc corrodes and
dissolves preferentially, releasing electrons to make the protected steel structure the cathode, thereby effectively
inhibiting or significantly slowing its corrosion rate, forming a “self-sacrificing” protective mechanism.
The self-sacrificing guardian: Zinc anodes provide long-term protection for large metal structures (such as ships,
offshore platforms, underground pipelines, storage tanks, and bridge foundations) through their continuous, controlled
dissolution and consumption, significantly extending their service life without requiring an external power source.
Cost-effective protection strategy: Compared to expensive coating maintenance or impressed current systems, zinc anode
systems have low initial investment costs, are easy to install, require no maintenance of power supply or complex
monitoring equipment, and offer superior cost-effectiveness over their entire lifecycle.
Excellent electrochemical performance: Zinc anodes have a high electrochemical equivalent (i.e., the amount of
electricity they can provide per unit weight), a stable operating potential, and high current efficiency (the ratio of
actual output electricity to theoretical electricity), ensuring stable output of protective current and efficient
utilization of materials.
Environmental compatibility: The corrosion products of zinc are relatively non-toxic and easy to handle, with minimal
cumulative impact in marine environments.
Challenges and ongoing evolution
Zinc cathode technology is not without challenges:
Chargeability issues: In aqueous batteries, zinc anodes are prone to dendrite formation (causing short circuits) and hydrogen
evolution reactions (reducing efficiency) during cycling, limiting their widespread application in high-performance rechargeable
batteries. Research into new electrolytes (such as weakly acidic, high-salt concentration, gel/solid-state electrolytes), electrode
structure optimization (such as three-dimensional current collectors, surface modification), and additives is currently a
hotspot for overcoming these bottlenecks.
Corrosion rate control: In sacrificial anode applications, precise design of anode composition (e.g., adding aluminum or
cadmium to optimize performance), shape, size, and distribution is required to ensure uniform protective effects and a
service life matching the protected object's requirements. The development of high-purity zinc and specific alloys has
enhanced performance stability.
Efficiency improvement: Continuous optimization is ongoing for both battery charge/discharge efficiency and sacrificial
anode current efficiency, aiming to reduce side reactions and maximize material utilization.
Bright prospects for the future
The future of zinc cathode technology is full of opportunities:
A Rising Star in Large-Scale Energy Storage: Zinc-ion batteries and zinc-based flow batteries based on aqueous electrolytes,
with their inherent safety, low cost, and environmental friendliness, demonstrate significant potential in large-scale grid
energy storage and renewable energy grid integration and peak shaving, serving as an important complement to
lithium-ion battery technology.
Support for Flexible/Wearable Electronics: Flexible zinc-based batteries (such as zinc-manganese dioxide and zinc-air) are
highly suitable for powering emerging wearable devices, electronic skin, and implantable medical devices due to their
safety and deformability.
Foundation for marine engineering and infrastructure: As global demands for marine resource development and
infrastructure durability continue to rise, the demand for high-performance, long-life zinc alloy sacrificial anodes will
grow steadily. The integration of protective design with intelligent monitoring will further enhance protective efficacy.
A key component of the circular economy: Zinc's high recycling rate (far exceeding that of lithium) is a significant
advantage. With the continuous advancement of recycling technologies (such as advanced hydrometallurgy), the
closed-loop recycling of zinc cathode materials in battery and protective applications will become more mature,
significantly reducing resource consumption and environmental impact, perfectly aligning with the principles
of the circular economy.
Zinc cathodes, whether used as battery anodes to release energy or as sacrificial anodes to protect steel, leverage
their unique attributes of safety, reliability, cost-effectiveness, and environmental friendliness to play an irreplaceable
role in the two critical fields of energy storage and metal protection. In the face of technical challenges, ongoing
research and development innovations are continuously expanding their performance boundaries and application
scenarios. In the global trend toward green and sustainable development, zinc cathode technology, with its resource
endowments and ecological advantages, is poised to embrace broader development opportunities, continuing to
contribute core value to the construction of a safe, efficient, and environmentally friendly future.