Sodium iron phosphophosphate (NaFePO₄F), often referred to as NFPP,
is a novel cathode material for sodium-ion batteries. It offers
several advantages, particularly in terms of cost-effectiveness and
resource sustainability, making it a focal point of research in the
field of sodium-ion batteries.
Product Overview
NFPP is a cathode material based on iron and phosphorus compounds.
It provides a relatively high theoretical specific capacity,
typically around 120-130 mAh/g, which is comparable to some
lithium-based cathode materials.
Key Characteristics
- High Energy Density: NFPP offers a relatively high theoretical specific capacity,
typically around 120-130 mAh/g, which is comparable to some
lithium-based cathode materials.
- Good Stability: The material exhibits good thermal and chemical stability, making
it safer and more reliable in battery applications.
- Low Cost: Due to the abundance of sodium and the use of inexpensive
precursors, NFPP has the potential to be a cost-effective
alternative to lithium-based cathodes.
- Environmental Sustainability: The production of NFPP involves fewer critical raw materials and
lower environmental impact compared to lithium-based materials.
Structure and Synthesis
NFPP typically crystallizes in the olivine structure, similar to
lithium iron phosphate (LFP). The synthesis of NFPP involves
high-temperature solid-state reactions or sol-gel methods, often
using precursors such as iron salts, phosphoric acid, and sodium
salts.
Electrochemical Performance
- Rate Capability: NFPP shows reasonable rate capability, although it may not match
the high rates of some other sodium-based cathodes.
- Cycling Performance: The material demonstrates good cycle life, with capacity
retention over multiple charge-discharge cycles, making it suitable
for long-term applications.
- Voltage Profile: NFPP typically operates at a voltage range of about 3.4-3.5 V vs.
Na/Na⁺, providing a stable output.
Applications
NFPP is being explored for various sodium-ion battery applications,
including:
- Grid Storage: Due to its cost-effectiveness and sustainability, NFPP is
suitable for large-scale energy storage solutions.
- Electric Vehicles: While still in the research phase, NFPP could offer a viable
option for EVs where cost is a significant factor.
- Portable Electronics: For devices where cost and sustainability are important, NFPP
could be a competitive alternative to lithium-ion batteries.
Future Prospects
Ongoing research aims to improve the performance of NFPP through
structural modifications, doping, and optimization of synthesis
processes. Enhancements in energy density, rate capability, and
cycle life are key areas of focus to make NFPP a mainstream
material for sodium-ion batteries.
In summary, NFPP represents a promising alternative to
lithium-based cathodes, offering a balance of performance, cost,
and sustainability for various energy storage applications.
| Test Item/Parameter | Unit | Specification | Test Result |
| Physical Indicators | | | |
| Appearance | / | Gray-black powder, uniform color, no hard lumps | Gray-black powder, uniform color, no hard lumps |
| Particle Size Distribution D10 | μm | ≥0.4 | 0.576 |
| Particle Size Distribution D50 | μm | 2.5±0.5 | 2.255 |
| Particle Size Distribution D90 | μm | ≤8.5 | 6.502 |
| Particle Size Distribution D100 | μm | ≤22 | 13.360 |
| Compaction Density | g/cm³ | 1.9±0.1 | 1.89 |
| Specific Surface Area | m²/g | 18±3 | 18.214 |
| pH Value | / | 10±1 | 10.34 |
| Moisture | ppm | ≤1000 | 780 |
| Chemical Indicators | | | |
| Main Element Content | Na | % | 14.9±0.5 |
| Fe | % | 24.2±0.5 |
| P | % | 20.1±0.5 |
| C | % | 2.5±0.5 |
| Impurity Element Content | Cr | ppm | ≤50 |
| Zn | ppm | ≤50 |
| Cu | ppm | ≤10 |
| Ni | ppm | ≤50 |
| Mn | ppm | ≤200 |
| Mg | ppm | ≤100 |
| Magnetic Substance Content | ppm | ≤1000 | 675 |
| **Half-Cell Data (1.5-4.0V)** | | | |
| 0.1C Capacity | mAh/g | ≥95 | 99.99 |
| 1C Capacity | mAh/g | ≥95 | 95.54 |
| 5C Capacity | mAh/g | ≥90 | 93.35 |
| First Cycle Efficiency | % | 100±5 | 100.56 |
| Average Voltage | V | ≥2.8 | 2.89 |
| 100C Capacity Retention | % | ≥95 | 96.72 |
| 1 | Specific Capacity | mAh/g | 116 | 110 | ≥120 | ≥110* | Button cell, 4.25V-1.75V, 0.1C |
| 2 | First Charge Efficiency | % | 86.2 | 89.9 | ≥92 | ≥90* | Button cell, 0.1C first charge discharge efficiency not less than
90% |
| 3 | Voltage Platform (during discharge) | V | 3.02 | 3.03 | ≥3.0 | ≥3.4* | Button cell, 0.1C first discharge voltage not less than 3.0V |
| 4 | Rate Performance | % | 89.9 | 91.6 | ≥92 | ≥92* | Button cell, IC discharge ratio capacity not less than 0.1C
discharge ratio capacity of 92% |
| 5 | High Rate Performance | % | 80 | 81.2 | ≥85 | ≥85* | Button cell, discharge ratio capacity not less than 0.1C discharge
ratio capacity of 85% |
| 6 | Cycle Performance | % | 97.6 | 97.1 | ≥98 | ≥92* | Button cell, IC charge-discharge cycle 200 times after discharge
ratio capacity not less than first discharge ratio capacity of 92% |
