Dry-Process Electrode Sheets: The Pivotal Material Linking Lithium-Ion Batteries and Supercapacitors

In the landscape of new energy storage technologies, lithium-ion batteries (LIBs) and supercapacitors stand as two core branches—LIBs support the long-range needs of electric vehicles and energy storage stations with their high energy density, while supercapacitors excel in instantaneous power regulation scenarios thanks to their high power density and long cycle life. Despite their seemingly distinct application directions, these two technologies share a critical material breakthrough: dry-process electrode sheets. This electrode component, manufactured via a solvent-free dry process that abandons traditional solvents, is addressing technical bottlenecks in both LIBs and supercapacitors with its "high performance, low energy consumption, and broad adaptability" characteristics, emerging as a core link connecting the two energy storage fields.

I. The "Performance Upgrade Key" for LIBs: Dry-Process Electrodes Solving Three Core Pain Points

The energy density, fast-charging capability, and safety of LIBs have long been constrained by electrode manufacturing processes. Traditional wet-process electrode sheets require mixing slurries with organic solvents such as NMP; the drying process not only consumes high energy and leaves residual impurities but also causes the collapse of electrode micropores, limiting ion transport efficiency. Dry-process electrode sheets, however, restructure the electrode’s microstructure through a "solvent-free" process, precisely addressing three core pain points of LIBs.

Boosting Energy Density to Break Range Limits

The energy density of LIBs hinges on the loading of active materials in the electrode. In wet-process technology, solvent occupation limits the active material loading rate to below 90%; dry-process electrode sheets, through dry powder mixing and precision calendering, can increase this loading rate to over 95% while avoiding micropore structure damage caused by solvent evaporation. Taking lithium iron phosphate (LFP) batteries as an example: positive electrodes prepared via the dry process have a compaction density increased from 3.6 g/cm³ (wet process) to 3.9 g/cm³. When paired with silicon-based anodes, the battery’s energy density exceeds 200 Wh/kg—15% higher than that of wet-process batteries—directly extending the range of electric vehicles from 500 km to 700 km.

Accelerating Ion Transport to Unlock Fast-Charging Capability

The core bottleneck for LIB fast charging lies in electrode internal resistance and ion migration rate. Wet-process electrodes often form "ion transport dead zones" due to uneven binder distribution; dry-process electrodes, by contrast, achieve uniform dry mixing of conductive agents (e.g., carbon nanotubes, graphene) with active materials, constructing a 3D conductive network that increases ion migration rate by more than 3 times. An automaker’s LIBs equipped with dry-process electrodes achieve "80% charge in 10 minutes," with charging efficiency approaching that of refueling traditional gasoline vehicles, resolving the range anxiety of electric vehicle users.

Enhancing Structural Stability to Fortify Safety

Residual organic solvents in wet-process electrodes tend to decompose and generate gas during battery cycling, increasing the risk of battery swelling and thermal runaway. Dry-process electrodes have no solvent residues, and their dense structure formed via dry calendering effectively suppresses the 400% volume expansion of silicon-based anodes. Needle penetration test data shows that LIBs with dry-process electrodes have a thermal runaway temperature 40°C higher than those with wet-process electrodes, with no fire or explosion—providing safety guarantees for scenarios such as energy storage stations and home energy storage.

II. The "Application Expander" for Supercapacitors: Dry-Process Electrodes Activating High-Power Potential

While supercapacitors are known for their high power density, their low energy density and high internal resistance have long limited their application in long-duration energy storage scenarios. Dry-process electrode sheets, with their precise control over pore structure and optimized conductive networks, are injecting new vitality into supercapacitor applications.

Optimizing Pore Structure to Balance Power and Energy

The energy density of supercapacitors depends on electrode specific surface area, while power density is related to ion transport channels. Wet-process supercapacitor electrodes often suffer from micropore blockage due to solvent evaporation during drying, resulting in a specific surface area typically below 1500 m²/g. Dry-process electrodes, by adjusting calendering pressure, can precisely control porosity between 30% and 60%, constructing a hierarchical pore structure of "macropores for energy storage and micropores for mass transfer" and increasing specific surface area to over 2000 m²/g. For example, electric double-layer supercapacitors with dry-process electrodes see their energy density increase from 5 Wh/kg to 12 Wh/kg while maintaining a high power density of 10 kW/kg. This has enabled successful application in rail transit braking energy recovery systems—a light rail line in a city equipped with such supercapacitors recovers 0.8 kWh of electricity per braking cycle, saving an average of 120 kWh of energy per train per day.

Reducing Interfacial Impedance to Extend Cycle Life

The cycle life of supercapacitors is affected by the stability of the electrode-electrolyte interface. Wet-process electrodes typically have an interfacial impedance above 50 mΩ due to residual binders. Dry-process electrodes use dry binders compatible with electrolytes (e.g., PTFE fibers) and achieve tight bonding between electrodes and current collectors via high-temperature calendering, reducing interfacial impedance to below 20 mΩ. Cycling test results show that supercapacitors with dry-process electrodes retain 90% of their capacity after 100,000 charge-discharge cycles, compared to only 75% for those with wet-process electrodes—significantly lowering maintenance costs for industrial equipment.

III. Process Commonality: The Underlying Logic of Dry-Process Technology Linking Two Fields

The ability of dry-process electrode sheets to adapt to both LIBs and supercapacitors stems from the shared advantages of their "solvent-free" process and precise alignment with electrode performance requirements.

From a process perspective, both technologies benefit from the "cost reduction and carbon emission reduction" features of dry-process technology. Wet-process manufacturing for both LIBs and supercapacitors requires solvent recovery equipment (accounting for 15%-20% of production line costs), and drying energy consumption accounts for over 30% of total energy use. The dry process eliminates solvent procurement, recovery, and drying steps, reducing investment in 1 GWh production lines by 20% and energy consumption by 40%—aligning with "dual carbon" goals. An energy storage enterprise’s calculations show that adopting dry-process electrodes reduces the comprehensive production costs of LIBs and supercapacitors by 12% and 18%, respectively, laying the foundation for large-scale application.

From a performance perspective, both technologies require electrode structures with "high conductivity and high stability." Ion transport in LIBs and charge adsorption in supercapacitors essentially rely on the electrode’s conductive network and microstructural stability. Dry-process electrodes achieve uniform dispersion of conductive agents through dry mixing and form dense structures via calendering, simultaneously meeting the high energy demands of LIBs and high power demands of supercapacitors—realizing "one material for multiple uses" technical synergy.

From extending LIB range to expanding supercapacitor scenarios, dry-process electrode sheets are emerging as a pivotal material linking the two energy storage fields, driven by their triple advantages of "performance adaptability, process synergy, and cost optimization." As dry-process technology further adapts to material systems such as high-nickel cathodes, silicon-based anodes, and composite electrolytes, it will not only drive LIB upgrades toward "higher energy and faster charging" but also help supercapacitors break through toward "longer-duration storage and wider temperature range applications." Ultimately, this will build a full-scenario energy storage material system covering "long range, fast response, and high safety," injecting core impetus into the high-quality development of the new energy industry.