Graphene material was born in 2004 and was first discovered in the laboratory by two scientists Andre Jem and Kostya Novoselov from the University of Manchester in the United Kingdom. To put it simply, graphene separates the stacked carbon atoms in graphite into single or double layers. For example, the traces left by a pencil on paper may be several layers or even a single layer of graphene.
Graphene is the thinnest and hardest nanomaterial known in the world. It is almost completely transparent, and its thermal and electrical conductivity are also very suitable for new electronic materials, such as battery electrode materials. Iron Man Musk once predicted that electric vehicles with built-in graphene polymer batteries can have a range of 800 kilometers in the future, reaching the endurance level of traditional cars.
1. The principle of graphene battery:
The test of graphene battery self-charging using environmental heat. The experiment made a circuit which contained LEDs, connected to the ribbon graphene with wires. They just put graphene in a copper chloride solution and observed it. The LED light is on. In fact, they need 6 graphene circuits to form a series connection, so that they can generate the required 2V to make the LED light bright, and you can get this picture.
Xu Zihan and colleagues said that what happened here is that copper ions have a double positive charge and pass through the solution at a speed of about 300 meters per second because of the thermal energy of the solution at room temperature. When the ion violently crashes into the graphene ribbon, the collision will generate enough energy to make the electrons that are not in situ leave the graphene. There are two options for electrons: they can leave the graphene ribbon and combine with copper ions, or they can pass through graphene and enter the circuit.
It turns out that the flowing electrons are faster in graphene, exceeding its speed through the solution, so the electrons will naturally choose their path through the circuit. It is this point that lights up the electrons released by the LED light more tend to pass through the graphene surface rather than into the electrolyte. This is how the device generates voltage.
Therefore, the energy generated by this device comes from the heat of the surrounding environment. They can increase the current by heating the solution, or use ultrasound to accelerate the copper ions. Relying only on the surrounding heat, they can keep their graphene batteries running for 20 days. However, there is an important question mark. Another hypothesis is that some chemical reaction produces electricity, just like a normal battery. However, Xu Zihan and colleagues said that they ruled out this because they conducted several control experiments.
However, these are introduced in some supplementary materials, and they do not seem to be placed on the arXiv website. They need to make public before anyone else makes a serious statement. At face value, this seems to be a very important achievement. Others also generate overcurrent in graphene, but just let water flow through it, so this is not really surprising, moving ions can also produce this effect. This heralds a clean, green battery, driven only by environmental heat. Xu Zihan and colleagues said: 'This represents a huge breakthrough, and the research is on self-driving technology.'
2. Graphene battery technology:
Technical breakthroughs in graphene-based high-temperature lithium-ion batteries mainly come from three aspects:
Special additives are added to the electrolyte to remove trace amounts of water and avoid high-temperature decomposition of the electrolyte;
The positive electrode of the battery adopts modified large single-crystal ternary material to improve the thermal stability of the material;
The new material graphene is used to achieve efficient heat dissipation between the lithium-ion battery and the environment.