The DRILL interface is making precision ion soft landing a benchtop reality, opening new doors for energy storage and beyond.
Benchtop Precision
Better Batteries
Molecular Control
Every battery, every supercapacitor, and every fuel cell that powers our world has a secret life at its interface. This is the invisible frontier where two different materials meet and transform, where energy is stored and released through a complex dance of chemical and electrical processes.
For decades, scientists have struggled to understand and control this chaotic interface, as it's buried within the device and teeming with different molecules.
"What if we could build this interface piece by piece, in a perfectly controlled way?" This is the question that drove researchers to develop a technique called ion soft landing (ISL) 1 3 5 .
Precise molecular placement for better energy storage
Using electric or magnetic fields, a specific ion type is selected based on its mass and charge 5 .
Studying the complete, messy interface all at once with multiple interacting components.
Selecting and placing individual ions to create pristine, well-defined surfaces for study.
While ion soft landing has been a valuable research tool, its need for expensive and complex vacuum systems limited its widespread use. The Dry Ion Localization and Locomotion (DRILL) interface, pioneered by Fedorov and co-workers, has changed the game 1 .
Solution pushed through capillaries with high voltage applied to create charged droplets.
Droplets enter DRILL chamber where heated nitrogen gas evaporates solvent.
Ions are guided by charged plates to ensure controlled beam.
Ions land gently on target surface at ambient pressure 1 .
Researchers aimed to deposit discrete, well-defined polyoxometalate (POM) anions—specifically PMo₁₂O₄₀³⁻—onto carbon nanotube (CNT) electrodes 1 .
POMs are excellent for redox supercapacitors, but their performance is maximized only when they are evenly distributed as single molecules, not clumped together in aggregates 1 .
When analyzed using high-resolution electron microscopy (HAADF-STEM), the results revealed discrete, individual POM molecules deposited uniformly across the surface 1 .
This was strikingly different from traditional electrospray deposition, which leads to large, irregular aggregates.
The POM-coated electrode demonstrated energy storage capacity similar to those prepared using sophisticated vacuum-based soft landing 1 .
A solution containing the POMs is loaded into the DRILL interface's syringe system.
Solution pushed through four fused silica capillaries with high voltage (-7 kV) applied.
Droplets enter DRILL chamber with heated nitrogen gas (175°C) to evaporate solvent.
Ions guided by charged plates onto CNT electrode at ambient pressure 1 .
Key materials and reagents for ion soft landing experiments
| Item Name | Function in the Experiment |
|---|---|
| Polyoxometalates (POMs) | The "star" ions; redox-active molecules used to create efficient energy storage interfaces 1 7 . |
| Carbon Nanotube (CNT) Electrodes | A highly conductive, high-surface-area substrate that serves as the platform for building the model energy storage device 1 7 . |
| Vertically Aligned Substrates (e.g., TiO₂ Nanotubes) | 3D semiconductive or conductive substrates used to study how ions penetrate and distribute within complex structures for real-world applications 7 . |
| Fused Silica Capillaries | The electrospray emitters; they transport the sample solution and, under high voltage, generate the charged droplets for ionization 1 . |
| High-Purity Nitrogen Gas | The drying gas that creates the vortex within the DRILL interface, responsible for efficiently desolvating the charged droplets 1 . |
Discrete, individual POM molecules confirmed by electron microscopy
| Substrate Type | Substrate Height | Penetration Depth |
|---|---|---|
| TiO₂ Nanotubes (Semiconductive) | 6-10 μm | Top 1.5 μm |
| Vertically Aligned CNTs (Conductive) | 300 μm | Top 40 μm |
Ions formed microaggregates on semiconductive substrates with limited penetration, but were uniformly distributed with much deeper penetration on conductive substrates 7 .
Traditional Method
Aggregates Formed
DRILL Interface
Discrete Molecules
Vacuum ISL
High Precision
Researchers at Pacific Northwest National Laboratory (PNNL) have pioneered a technique to simultaneously select and deposit both positive and negative ions, creating a more realistic model of energy storage devices where different ions interact with each other and the surface 5 .
The latest research is moving beyond mass selection alone. Scientists are now using Structures for Lossless Ion Manipulations (SLIM) to separate ions based on their size and shape (ion mobility) before soft landing 6 .
This allows for isomer-selective deposition—placing one specific structural variant of a molecule on a surface while excluding others—opening new frontiers in nanofabrication and molecular characterization 6 .
The democratization of ion soft landing through tools like the DRILL interface marks a significant shift in materials science and energy research. By transforming a once-esoteric technique into a broadly accessible benchtop process, scientists are no longer just observers of complex interfaces; they are now their architects.
As researchers continue to build functional devices—from supercapacitors with unparalleled capacity to next-generation batteries—one precisely landed ion at a time, the promise of a more energy-efficient future becomes ever more tangible. This gentle landing is making a powerful impact, enabling us to build the energy solutions of tomorrow from the molecular level up.