Introducing FlexRAM: The First Fully Flexible Liquid Metal Memory

A science fiction device more reminiscent of Hollywood than an apparent reality in 2024. Yet, the world does not stand still; it needs new devices and materials to continue advancing toward a future that may sound dystopian but is already here. FlexRAM offers something never achieved before in history – a flexible, resistive, metal, and liquid random access memory device!

The metal referred to is gallium, a commonly used element in the field of semiconductors, especially in thermal pastes. The mental image of the liquid Terminator comes to mind. The concept, albeit more basic than the film, uses similar principles, transforming what was once a fantasy of cinema into reality.

FlexRAM: China achieves the first liquid metal, scalable random access memory

The base material is gallium, but more components are involved in the process. The material, announced by China in the journal Advanced Materials, is described in the following way:

“Inspired by human brain polarization and depolarization mechanisms, we propose a new class of storage principles and achieve fully flexible memory by introducing oxidation and reduction behaviors of liquid metals.”

What does this mean? It may not be easy to explain, as one must erase the preconceived memory of computers, laptops, or mobile phones. Imagine a drop of gallium (GLM) dense enough to stretch to the limit without breaking. This deformation does not affect performance unless a rupture occurs, and it is in a specific solution. That is, the GLM drop is surrounded by a dense liquid, like jelly.

With this mental image, the explanation can proceed. Gallium (GLM) is used to achieve oxidation and reduction mechanisms using the jelly-like solution to facilitate hyperpolarization and depolarization. But how does this new memory store data?

Hyperpolarization, commonly known as positive polarization, represents a binary 1, while depolarization (negative polarization) represents a 0. Applying a low voltage oxidizes the liquid metal surrounding the gallium, registering a binary 1. By reversing polarity, a binary 0 is obtained. The challenge now is to achieve high-speed storage of data without losing any, and with precision, durability, and flexibility. FlexRAM accomplishes this, albeit at a basic level for now.

Using a computer, researchers have encoded a string of letters and numbers in binary form. With eight FlexRAM devices in an array, they can store one byte of data. The data transfer process involves pulse modulation (PWM) to control the oxidation and reduction of gallium.

The researchers report early-stage results with FlexRAM. With minimal exposure to oxygen, the memory can retain data for up to 43,200 seconds, or 12 hours, and can withstand 3,500 operation cycles. They claim speeds exceeding 33 Hz, a remarkable achievement for such a nascent technology. As for the size, they mention millimeter drops, but nanometric sizes are also possible. Interestingly, as the size shrinks, the memory becomes more sensitive, which may be both an advantage and a challenge in reducing the form factor.

FlexRAM could find applications in a variety of liquid, flexible, and moldable computer systems, even as standard logic devices. Potential uses include clothing, accessories, adaptable hardware for various surfaces, mobile devices conformable to the human body, and any shape-shifting requirement.

The introduction of FlexRAM marks the beginning of the first fully flexible liquid metal memory.