Sodium-ion cathode sheets.
Built to your spec.
NVP, P2, NFPP, and high-entropy layered oxides — pre-coated on aluminum foil for Na-ion research.
Every sheet made to order. Specify loading, substrate, cut size — we calibrate to your target.
Why Na-ion is back, and why the cathode is the bottleneck.
Sodium-ion batteries (SIBs) are not the "poor cousin" of lithium-ion. They are the chemistry that finally has the cost structure, the supply-chain independence, and — by 2025–2026 — the energy density to compete with LFP at the entry-level EV and stationary storage segments. CATL launched its first commercial Na-ion product in 2023. BYD, HiNa, Faradion, and Northvolt all have Na-ion programs in pilot or early mass production. The bottleneck is no longer "does the chemistry work" — it's which cathode chemistry to commit to, and that's where research-stage decisions made today shape pilot lines two years out.
If you only optimize the anode or the electrolyte, you are polishing the parts of the cell that contribute the least to Na-ion's commercialization timeline. Anode hard carbon is mature. Electrolyte adapts from Li-ion know-how. The cathode is where chemistry, cost, and cycle life are decided. Sodium is not on the USGS critical minerals list, unlike lithium and cobalt — a strategic supply-chain advantage that's driving the chemistry's commercialization. Xnergy's full Na-ion cathode electrode sheet catalog is structured around four production-grade chemistries, each built to your loading and cut specification.
How a sodium-ion cathode actually works.
The Na-ion cell operates on the same intercalation principle as Li-ion: ions shuttle between the cathode and anode through an electrolyte while electrons flow through the external circuit. What changes — and what makes Na-ion cathodes a separate engineering problem — is the ion itself.
The sodium ion is ~30% larger than the lithium ion (1.02 Å vs. 0.76 Å). This single geometric fact cascades into every design choice:
- Layered oxide structures must be more "open" to accommodate Na transport — which is why P2-type and O3-type sodium oxides exist as distinct phases, while lithium oxides default to O3.
- Lattice volume change during cycling is larger, which stresses grain boundaries and causes capacity fade.
- Voltage plateaus are 0.3–0.5 V lower than the Li analog, which lowers gravimetric energy density at the same capacity.
- Polyanionic frameworks shine in Na-ion in a way they don't in Li-ion, because strong P–O bonds offset the larger ionic radius with structural rigidity.
Three structural families dominate Na-ion cathode research today: layered transition metal oxides (NaₓTMO₂, split into P2-type and O3-type), polyanionic phosphates (NVP, NVPF, NFPP — built on NASICON frameworks), and Prussian blue analogues (separate research thread, not the focus here).
For researchers characterizing these structures in their own lab, in-situ X-ray diffraction cells make it possible to observe Na migration and phase transitions during cycling — complementary to the ex-situ characterization workflows documented by the U.S. National Institute of Standards and Technology.
The four chemistries Xnergy ships as electrode sheets.
NASICON polyanion
The benchmark polyanionic cathode for sodium-ion research. Its NASICON framework — a 3D network of corner-sharing PO₄ tetrahedra and VO₆ octahedra — gives it exceptional structural stability and a remarkably flat 3.4 V voltage plateau. The primary modification challenge is NVP's intrinsically low electronic conductivity, addressed in commercial products through carbon coating reviewed across the peer-reviewed literature.
- Capacity
- ~117 mAh/g theoretical · 110–115 mAh/g practical
- Voltage
- 3.4 V (very flat plateau)
- Used in
- Long-cycle research, fast-charging studies, reference electrodes
- Risk
- Vanadium cost and toxicity classification
- Order
- NVP (Na₃V₂(PO₄)₃) Sodium-Ion Cathode Sheet
Layered Na transition-metal oxide
The highest-capacity Na-ion cathode family in research today, delivering 130–160 mAh/g across the various Mn, Fe, Ni, and Cu compositions reported in the literature. The "P2" label refers to prismatic Na coordination geometry — open diffusion channels that enable fast Na transport and excellent rate capability. The trade-off is structural: above ~4.0 V, P2-type materials undergo an irreversible P2-to-O2 phase transition that progressively degrades cycle life.
- Capacity
- 130–160 mAh/g depending on composition
- Voltage
- 3.0–3.5 V (sloping)
- Used in
- High-energy research, P2-vs-O3 comparative studies, LFP-line drop-in candidates
- Risk
- P2-to-O2 phase transition above 4.0–4.2 V
- Order
- P2 Sodium-Ion Cathode Electrode Sheet (Multiple Specs)
Iron-based NASICON
Arguably the most important Na-ion cathode story of 2024–2026 from a commercialization standpoint. Built on the NASICON framework like NVP, but substitutes iron for vanadium — eliminating the vanadium cost, toxicity, and supply concerns that complicate NVP's scale-up path. HiNa Battery has standardized on NFPP for its first-generation grid-scale product. Recent research has demonstrated modified NFPP composites cycling 10,000+ times with single-digit capacity decay — performance levels that put NFPP in the same conversation as LFP for cycle life.
- Capacity
- ~110 mAh/g theoretical · 100–105 mAh/g practical
- Voltage
- 3.0–3.2 V
- Used in
- Cost-driven scale-up, grid-scale ESS research, long-cycle prototypes
- Risk
- Low electronic conductivity — carbon coating typically needed
- Order
- NFPP Sodium-Ion Cathode Sheet — Multiple Loadings
High-entropy layered oxide
The leading edge of layered-oxide research — a high-entropy composition where the configurational entropy of mixing multiple transition metals suppresses the destructive phase transitions that limit conventional P2 and O3 cathodes. The result is a layered oxide combining the high capacity of P2-type materials with cycle life closer to NASICON polyanions. High-entropy sodium cathodes have become a focal point in the academic literature since 2021–2022.
- Capacity
- 140–160 mAh/g (composition-dependent)
- Voltage
- 3.0–3.6 V
- Used in
- Advanced research, high-entropy material design, biphasic intergrowth
- Risk
- Research-stage; cycle data still maturing across the field
- Order
- Fe-Mn-Co-Ni-V Cathode Single-Sided Electrode Sheet
A complete Na-ion build needs more than the cathode. Xnergy also ships Na-ion anode electrode sheets, sodium metal materials for half-cell testing, and Na-ion-compatible salts, solvents, and formulations. See the full Na-ion materials catalog.
Side-by-side comparison. 2026 data.
Representative ranges for current research and early-commercial cells. Cycle life depends strongly on voltage window, rate, temperature, and structural modification.
| Cathode | Capacity | Voltage | Cycle Life | Cost Driver | Best For |
|---|---|---|---|---|---|
| NVP | ~117 mAh/g | 3.4 V | 4,000+ | Vanadium | Long-cycle reference |
| NVPF | ~115 mAh/g | 3.95 V | 1,000–2,000 | V + F | High-voltage energy |
| NFPP | ~110 mAh/g | 3.2 V | 4,000–10,000+ | Iron — lowest | Cost-driven ESS |
| P2 layered | 130–160 mAh/g | 3.0–3.5 V | 500–1,500 | TM abundance | Energy density, rate |
| O3 layered | 100–140 mAh/g | 2.7–3.4 V | 1,000–2,000 | TM abundance | LFP-line drop-in |
| HE layered (5-element) | 140–160 mAh/g | 3.0–3.6 V | 1,000+ (rising) | Multi-TM | Advanced research |
| PBA | 100–130 mAh/g | 3.0–3.5 V | 500–2,000 | Very low | Aqueous, low-cost ESS |
Built to your spec.
Every Xnergy Na-ion cathode sheet ships as a custom-built order. Three specifications you choose at the time of quote.
Active material loading
Loading determines areal capacity (mAh/cm²) and downstream cell-level performance.
- Standard research range available as catalog SKUs
- Ultra-thin loadings for rate studies
- High-load variants for pouch prototypes
- Specify target mg/cm² or target mAh/cm² at quote
Send your N/P ratio and anode pairing — our engineers will recommend a matched cathode loading.
Substrate
Aluminum foil is the standard current collector. Na-ion can use Al on both electrodes (sodium does not alloy with Al at low potential), a small BOM advantage over Li-ion.
- Standard battery-grade Al foil
- Thinner foil for high-energy research
- Thicker foil for high-load pouch builds
- Carbon-coated Al for lower contact resistance
- Single- or double-sided coating
Cut dimensions
Standard sheets ship as research-format rectangles. We also pre-cut to:
- Discs matched to CR2016 / CR2025 / CR2032
- Rectangular strips for Swagelok and pouch cells
- Custom shapes from a DXF or PDF drawing
- Research-grade tolerance
How to choose the right cathode sheet.
Walk through these four questions in order. The right answer almost always determines which downstream materials and equipment you'll also need.
Cost, cycle life, or energy density?
- Cost (LFP-class target) → NFPP (no vanadium)
- Cycle life → NVP or modified NFPP
- Energy density → P2 layered or high-entropy layered
Pre-coated sheets or raw powder?
Electrode sheets save 4–8 weeks of in-house slurry development, coating optimization, and calendaring iteration — right for early benchmarking. For pilot-scale formulation work, source cathode material powder and pair with our coating, slurry mixing, and calendaring equipment.
Single-sided or double-sided?
Coin cells and most half-cell research use single-sided sheets. Full pouch cells, cylindrical cells, and any anode-symmetric architecture need double-sided coating. Specify at quote.
What's your electrolyte strategy?
Na-ion electrolytes are not interchangeable with Li-ion. NaPF₆ in carbonate solvents is the workhorse; NaClO₄ and NaFSI variants are research alternatives. Mismatching salt to cathode is a common cause of premature capacity fade. Browse salts, solvents, and formulations, plus electrochemical testing equipment for CV and EIS validation.
See our parallel deep-dive on Lithium-Ion Battery Cathode Materials: The Complete 2026 Guide, and the broader procurement framework in Battery Research Materials: A Complete Buyer's Guide.
Three trends reshaping Na-ion cathodes in 2026.
High-entropy cathodes go mainstream.
High-entropy layered oxides — five or more transition metals mixed in near-equiatomic ratios — are doing for Na-ion what single-crystal NCM did for Li-ion: pushing cycle life higher at the high-voltage edge. The configurational entropy of mixing suppresses destructive P2-to-O2 and O3-to-P3 phase transitions. Research published in Joule and Nature Energy has accelerated since 2022. Xnergy's Fe-Mn-Co-Ni-V five-element cathode sheet is one of the first commercially available examples.
NFPP overtakes NVP for low-cost scale-up.
The 2017–2022 SIB research era was about proving the chemistry; NVP carried that load. The 2024–2026 era is commercial scale-up — and that's where NFPP overtakes NVP, because removing vanadium removes the largest remaining cost concern. Mg-doped NFPP composites and 3D carbon-network architectures have pushed laboratory cycle life past 10,000 cycles — an LFP-comparable number grid-scale ESS programs can plan around. The U.S. DOE Energy Storage Grand Challenge explicitly prioritizes earth-abundant chemistries.
First commercial Na-ion vehicles and ESS at scale.
CATL, BYD, JAC, HiNa, and Northvolt are all in pilot or early mass production of Na-ion products targeting entry-level EV and stationary storage. The IEA Global EV Outlook 2024 flagged Na-ion as the most likely chemistry to take share from LFP at the bottom of the market between 2025 and 2028. Cathode choices made today shape supply contracts for the second half of the decade.
Common pitfalls working with Na-ion sheets.
Drawing from common questions we get from research customers:
- Moisture sensitivity is worse than Li-ion, not better. Sodium surface compounds (NaOH, Na₂CO₃) form rapidly on exposed cathode surfaces. Keep opened sheet packaging sealed and handle layered-oxide and NFPP sheets in a dry room or argon glove box (≤1 ppm H₂O for high-end work).
- Electrolyte salt selection is not interchangeable. NaPF₆ is the default for organic Na-ion electrolytes; do not substitute LiPF₆ "just to test." Mismatched salts cause immediate capacity loss in the first cycle.
- Aluminum foil works on both electrodes — unlike Li-ion, where the anode needs copper. A real BOM saving, but requires that your assembly process not default to copper foil. See aluminum foil and copper foil for the comparison.
- Hard carbon, not graphite, on the anode. Sodium does not intercalate effectively into graphite. Standard Na-ion anode chemistry is hard carbon. See Na-ion anode electrode sheets.
- Voltage cutoff matters more for P2 than for NVP/NFPP. For P2 layered oxides, keep the upper cutoff conservative (typically ≤4.0 V) to avoid the P2-to-O2 phase transition. NASICON polyanions tolerate higher voltage windows.
- N/P ratio for Na-ion is not the Li-ion default. Hard carbon anodes have different first-cycle irreversibility profiles than graphite. Build the N/P ratio from your specific anode and cathode capacities, not from an inherited Li-ion recipe.
- Formation protocols differ. First-cycle SEI formation on hard carbon takes longer and is more sensitive to rate. Plan slow first cycles and longer rest periods. Browse coin cell assembly and pouch cell assembly equipment.
Frequently asked questions.
Sourcing Na-ion cathodes? Built to your spec.
A balanced research program treats the cathode as a design variable, not a stock catalog item. Specify your loading, substrate, and cut size. We'll quote within 24 hours.