To understand how the porous graphene helps, first you need to know how today’s lithium-ion batteries work. Like all batteries, lithium-ion cells contain a positive electrode (cathode) and a negative electrode (anode) separated by a chemical medium called an electrolyte and a semi-permeable barrier called a separator.
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When the battery is charged, lithium ions flow to the anode, which is made of graphite. The lithium ions stick to the surface of the graphite and also bury themselves deep in its layers, which is how the energy is stored. When the battery goes to work powering a device, the ions flow from the anode to the cathode, passing through the separator at a steady rate. At the same time, electrons are released at the anode, flow out into the external circuit, and eventually return to the cathode.
To recap, there are two processes that make batteries work, the transport and storage of ions between electrodes, and the release of electrons into the external circuit. To build a battery that stores more energy and recharges faster, you need to optimize the flow of both ions and electrons.