Detailed Introduction to Graphite Paper

Graphite Paper, also known as flexible graphite paper or expanded graphite paper, is a thin, flexible graphite product made from high-purity graphite as the core raw material through crushing, forming, rolling/exfoliation and other processes. It retains the inherent excellent properties of graphite while featuring processability such as cuttability, bendability and compoundability. As a key basic material for the new energy, electronics, chemical engineering, metallurgy and other industries, it is categorized into industrial sealing type, electronic thermal conductive type, conductive shielding type and others according to application scenarios, to meet the technical requirements of different industries.

I. Core Raw Materials and Preparation Processes

1. Core Raw Materials

It takes high-purity flake graphite (with a fixed carbon content of 99.0%~99.999%; high-end electronic grade requires more than 99.99%) as the main raw material. Some special graphite papers are modified by compounding with carbon fiber, metal foil, polymer film and other materials to improve strength, thermal conductivity or corrosion resistance.

2. Mainstream Preparation Processes

(1) Expansion and Rolling Method (mainstream in industry, high cost performance)

Core steps: Flake graphite undergoes acid intercalation → high-temperature expansion (volume expansion by 300~500 times to form vermicular expanded graphite) → roll forming → slitting and film coating to produce flexible graphite paper.

Features: Mature technology, good flexibility and bendability of products, suitable for large-scale mass production, mainly used in industrial sealing and conventional thermal conduction scenarios.

(2) Chemical Vapor Deposition (CVD) Method (high-end electronic grade)

Core steps: With inert gas as the carrier, carbon-containing gas is deposited on the substrate at high temperature → forming a high-crystallinity graphite film → exfoliating to obtain graphite paper.

Features: Ultra-high product purity, excellent thermal conductivity, micron-level thickness achievable, suitable for high-end electronic heat dissipation, but with complex technology and high cost.

(3) Ultrasonic Exfoliation Method (laboratory/pilot test stage)

Core steps: High-purity graphite is exfoliated by ultrasonic vibration → forming monolayer/few-layer graphene sheets → film forming and pressing to obtain graphite paper.

Features: Extremely thin products with excellent thermal/electrical conductivity; not yet mass-produced industrially, mainly used in the R&D of cutting-edge new materials.

 

 

II. Core Performance Characteristics

The core advantages of graphite paper stem from the lamellar crystal structure of graphite, combining the physicochemical properties of natural graphite with the processability of thin sheet materials. Its key properties are as follows:

High thermal conductivity: The in-plane thermal conductivity can reach 150~1800 W/(m·K) (＞1000 W/(m·K) for high-end electronic grade products), far superior to metals such as aluminum and copper. It is an efficient planar heat dissipation material with a low coefficient of thermal expansion and no obvious deformation during heat dissipation.

Excellent electrical conductivity: The in-plane volume resistivity is as low as 5~20 μΩ·cm, with good electrical and electromagnetic shielding performance, and can replace some metal conductive sheets.

Superior high and low temperature resistance: Stable performance in the range of -200℃~600℃ (up to 2800℃ in vacuum/inert environment), no softening or brittleness, and remains flexible with stable physicochemical properties in high and low temperature environments.

Chemical stability: Resistant to corrosion by strong acids, strong alkalis and organic solvents, and does not react with most chemical media. It only reacts with oxygen in high-temperature strong oxidizing environments, suitable for corrosive environments such as chemical engineering and metallurgy.

Good flexibility and processability: Can be bent and wound arbitrarily without easy fracture; can be cut, punched, film-coated and compounded according to requirements, suitable for the lamination of various special-shaped parts. It can also be compounded with aluminum foil, copper foil, silica gel, glass fiber cloth, etc., to improve comprehensive performance.

Low specific gravity & lightweight: With a density of only 0.8~2.2 g/cm³, much lower than metal materials, it is the first choice for lightweight heat dissipation and conductive solutions.

Non-toxic & environmentally friendly: Pure graphite-based products have no volatiles or hazardous substances, complying with RoHS, REACH and other environmental standards, and suitable for the environmental requirements of electronic and consumer products.

III. Product Classification and Key Parameters

Graphite paper is mainly classified by purity, application and thickness. The technical parameters and applicable scenarios of different categories vary significantly. The core classification and key indicators are as follows:

IV. Main Application Fields

With diverse properties and strong adaptability, graphite paper is widely used in new energy, electronic information, chemical sealing, electric power, metallurgy and other industries, serving as a cross-field basic functional material. Its core application scenarios are as follows:

1. Electronic Information Field (core application for heat conduction/shielding)

It is a key heat dissipation material for consumer electronics and industrial control equipment, solving the heat dissipation challenges caused by the "miniaturization and high power density" of electronic components:

Consumer electronics: Heat dissipation for chips and battery packs of mobile phones, laptops and tablets; it can be bent to fit special-shaped heat dissipation structures, replacing traditional thermal conductive silicone sheets and copper foils.

Industrial control/semiconductors: Planar heat dissipation for servers, base station equipment and chip packaging, as well as electromagnetic shielding parts to improve the anti-interference ability of equipment.

Optoelectronics: Heat dissipation for LED chips and photovoltaic inverters, adapting to outdoor high and low temperature environments.

2. New Energy Field (core growth track)

Power batteries: Inter-cell and module heat dissipation for battery packs of new energy vehicles and energy storage systems; realizing temperature uniformity through high thermal conductivity to avoid local overheating of cells and improve battery safety and service life.

Hydrogen energy industry: Sealing of bipolar plates and graphite electrode accessories for fuel cells, adapting to the working environment of fuel cells by virtue of corrosion resistance and electrical conductivity.

Photovoltaic industry: Electrically conductive connectors and inverter heat dissipation parts for photovoltaic modules, meeting the requirements of long-term outdoor use.

3. Chemical/Metallurgical Field (main force for industrial sealing)

As a high-end sealing material, it replaces traditional asbestos and rubber seals (asbestos has been banned, and rubber has limited temperature and corrosion resistance):

Chemical equipment: Static sealing gaskets for reaction kettles, pipes and valves; resistant to strong acids, strong alkalis, high temperature and pressure, adapting to the corrosive environment of chemical production.

Metallurgical equipment: Sealing and thermal insulation parts for steelmaking and aluminum smelting furnaces; withstanding high-temperature metallurgical environments without volatilization of hazardous substances.

4. Electric Power/Electrical Field

High and low voltage electrical equipment: Electrically conductive brushes and electrode gaskets for circuit breakers and disconnectors; improving contact conductivity with good electrical conductivity and flexibility.

New energy power generation: Sealing and electrically conductive connectors for wind power and hydropower equipment, adapting to harsh outdoor environments.

5. Other Special Fields

Aerospace: Lightweight heat dissipation and sealing parts for aviation equipment and satellites, withstanding the high and low temperature and vacuum environment of space.

Medical devices: High-precision heat dissipation and corrosion-resistant electrode accessories for medical equipment, complying with the environmental and precision requirements of medical devices.

Graphene composite materials: Served as the basic raw material for graphene preparation, used in the R&D of cutting-edge materials such as graphene films and graphene thermal conductive composites.

V. Storage and Processing Precautions

1. Storage Requirements

Store in a sealed manner in a dry and ventilated environment to avoid moisture (although graphite paper is non-hygroscopic, moisture absorption on the surface will affect the lamination and thermal conduction effect); control the ambient humidity at ≤60%.

Keep away from high-temperature and strong oxidizing environments (such as open flame, concentrated nitric acid, potassium permanganate and other oxidants) to prevent graphite oxidation.

Store flat to avoid excessive pressure and folding deformation; store roll-packaged graphite paper vertically to prevent interlayer adhesion.

2. Processing Precautions

Cutting/punching: Use high-precision cutting machines and punching machines with sharp tools to avoid edge powdering and fraying that may affect the lamination effect.

Lamination/compounding: Can be compounded with metal, plastic and other substrates by thermal conductive adhesive or double-sided adhesive; clean the surface of graphite paper to remove dust before compounding.

Transportation: Handle with care and use anti-static and moisture-proof packaging to avoid friction-induced powdering and extrusion deformation during transportation.

VI. Industry Development Trends

Driven by the rapid development of the new energy and electronic information industries, the market demand for graphite paper keeps growing, and the industry development presents four major trends:

High-endization: R&D of graphite paper with ultra-high purity (≥99.99%), high thermal conductivity (＞1000 W/(m·K)) and ultra-thin thickness (micron level) has become a key focus, adapting to high-end electronic, semiconductor, aerospace and other fields.

Composite development: Compound graphite paper with aluminum foil, copper foil, silica gel, glass fiber cloth and other materials to form "graphite paper + substrate" composite functional materials, which integrate multiple properties such as thermal conduction, electrical conduction, strength and sealing to improve adaptability.

Cost reduction: Optimize the expansion and rolling process, promote the industrial mass production of CVD and ultrasonic exfoliation methods, reduce the production cost of high-end graphite paper and expand its application scope.

Green development: Develop acid-free intercalation processes for expanded graphite preparation to reduce pollutant emissions in the production process and comply with environmental policy requirements.

VII. Core Advantages Compared with Similar Materials

Compared with traditional thermal conduction/sealing/conductive materials (copper foil, aluminum foil, silicone sheet, rubber seal), graphite paper has significant core competitive advantages: