SiMaxxTM Enables Superior Energy Density for High-Performance Applications
Silicon Anode Fabrication ProcessLearn how Amprius manufactures its ultra-high density silicon anode lithium-ion batteries!

We Enable the Future of Electric Mobility Today


  • High performance silicon anode batteries

Superior Battery Performance

  • High Energy Density
    • Up to 500 Wh/kg(1) and 1,300 Wh/L(1)(2)
  • High Power Density
    • Up to 10C
  • Fast Charge Rate Capability
    • 80% charge in <6 minutes(3)
  • Safety
    • Passed Military Performance Spec Nail Penetration test with 390 Wh/kg
  • Wide Operating Temperature
    • -30°C to 55°C

Commercially Proven

  • Tested and validated by industry leading partners

Note: Certain performance metrics are based on specific Amprius products.
(1) At C/10 and 23°C.
(2) Volumetric energy density is calculated using body dimensions at 30% state of charge (“SoC”).
(3) With 390 Wh/kg battery, available with SiMaxxTM

SIMAXXTM Silicon Anode Structure

100% Silicon Nanowires(1) Allow Volume Expansion without Binders, Graphite, or any Inactive Materials
Side View
Top View
Silicon Nanowires

Conventional Graphite Particles

  • Spacing between nanowires and silicon porosity accommodate silicon volume expansion
  • Ions and electrons travel straight paths
  • Most conductive path for ions and electrons results in high power capability and fast charge rate

(1) Actual percentage of silicon is 99.5-99.9% which is within the range of acceptable purity levels for materials that are considered 100%.

SICORETM Silicon Anode Structure

BOTTOM-UP Unique Structure4-layer structure innovation
ELASTIC Si-Nanostructure Interior StructureHighly isotropic, discontinuous structure
MULTILAYER Surface ProtectionIn-situ growth, complete encapsulation, fast lithium conduction
Alleviate expansion stressand reduce surface side reactions
Extend cycle lifeand improve high temperature stability
High-speed charge transferand high-rate performance


Why is battery technology evolving so slowly?

The main reason for the slow pace of battery improvement is chemistry. In conventional lithium-ion batteries the anode is made of carbon in the form of graphite, and graphite has reached its energy density limit.

A new anode material is required to improve battery performance, and that material is silicon. Silicon can store up to 10 times more lithium compared to graphite which enables batteries to have much greater energy. But silicon swells dramatically when it is charged with lithium and that can cause it to crack and stop working.


Advantages of Amprius’ silicon batteries

Highest content active silicon material
Silicon is the best material for energy density. Using more silicon means that we can provide lithium-ion batteries with higher energy density, while at the same time enabling the highest ratio of energy to power.

Excellent cycle life
Amprius Technologies’ Silicon Batteries have excellent cycle life that is continuously improving. This has been demonstrated in real world use with multiple organizations including US National Labs and major aerospace companies.

100% Silicon Anode (1) Has ~10x Capacity vs. Graphite


(1) Actual percentage of silicon is 99.5-99.9% which is within the range of acceptable purity levels for materials that are considered 100%.
(2) Based on Amprius measurements in half cells.



Revolutionizing battery technology
Amprius Technologies’ silicon lithium-ion batteries are game-changers. Having the highest energy density in the industry, our batteries can substantially improve the performance of electric vehicles, aircraft, drones, and wearables.

Urban Air Mobility – estimated flight time based on customer models
Soldier Power – real data based on Conformal Wearable Battery developed for US army
Smartwatch – customer-reported data
Electric Vehicle – estimated relative to Tesla Model 3 long-range battery specifications

Chart showing the present and future evolution of battery technology and performance

The All-New Amprius 500 Wh/kg Battery Platform is Here

FREMONT, Calif. – March 23, 2023Amprius Technologies, Inc. is once again raising the bar with the verification of its lithium-ion cell delivering unprecedented energy density of 500 Wh/kg, 1300 Wh/L, resulting in unparalleled run time. At approximately half the weight and volume of state-of-the-art, commercially available lithium-ion cells, the all-new battery cell delivers potential industry-disrupting performance with barrier breaking discharge times.
View Press Release

Amprius - Industry-Leading 500 Wh kg Battery Platform from PXLPod Web Strategy on Vimeo.

Industry-Leading 500 Wh/kg Battery Platform

Ultra-High Energy Density Lithium-Ion Batteries Deliver Unparalleled Run Time
The 500 Wh/kg battery platform is a tailored solution for applications that require maximum discharge times without compromising key features, such as aircraft payload. The new lithium-ion batteries demonstrate ultra-high gravimetric energy density (500 Wh/kg) and volumetric energy density (1300 Wh/L) enabling longer run times, range and endurance, while enabling lighter packs that increase energy efficiency.

Amprius Passes Nail Penetration Test

An independent third-party testing lab validated Amprius’ 390 Wh/kg polymer electrolyte cell by successfully passing the nail penetration test. Passing this test is important as Amprius cells have the potential to double energy content without increasing weight.

Amprius Extreme Fast-Charge Demonstration

Our commercially available 370 Wh/kg silicon anode battery demonstrated extreme fast charge rate of 0-80% state of charge in less than six minutes. Dr. Ionel Stefan explains the proprietary silicon nanowire anode technology and the unique battery characteristics that make it well positioned to address the electric mobility market.