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(picture source: Official Website of Illinois) lithium ion is prone to internal short circuit, causing electrolyte combustion, explosion and fire. Engineers at the University of Illinois have developed a solid polymer electrolyte to help manufacturers produce recyclable, self-healing commercial batteries, foreign media reported. The electrolyte can repair itself after being damaged, and can be recycled without the use of irritant chemicals or high temperature. After multiple charge and discharge cycles, lithium-ion batteries will form tiny lithium dendrites, which will shorten the battery life and cause hot spots and short circuits. Sometimes the lithium dendrites will grow larger and pierce the inside of the battery, resulting in an explosive chemical reaction between the electrode and the electrolyte. Chemists and engineers have long wanted to replace liquid electrolytes in lithium-ion batteries with solid materials such as ceramics or polymers, the researchers said. However, most of these materials show rigidity and brittleness, which leads to poor contact between electrolyte and electrode and reduces conductivity. Brian Jing, a graduate student in materials science and engineering, one of the researchers, said: "if solid ionic conducting polymers are used as non-liquid electrolytes, in the high temperature environment inside the battery, most of the polymers will be melted, leading to dendrite growth again, causing failure." In the past research, people used the network polymer chain which was cross-linked to form rubber lithium conductor to produce solid electrolyte to delay the dendrite growth. However, these materials are complex in structure and cannot be recovered or healed after damage. In order to solve this problem, researchers developed a kind of network polymer electrolyte, whose crosslinking point can exchange reaction and exchange polymer chain. Compared with linear polymers, these reticulated materials become harder when heated, minimizing dendrite problems, the researchers said. Moreover, after damage, it is easy to decompose and form a network structure again, so it can be recycled to restore conductivity. "The outstanding performance of the new network polymer is that its conductivity and rigidity will gradually increase during the heating process," said Jing. This is not seen in conventional polymer electrolytes. " "Most polymers need strong acid and high temperature to decompose," said Christopher Evans, a professor of materials science and engineering and a leading researcher. "Our materials can be dissolved in water at room temperature, which is very energy-saving and environmentally friendly." The researchers tested the conductivity of the new material and believed that it has the potential to become an effective battery electrolyte. However, there is still a long way to go to achieve the same performance as the current electrolyte. "We add a very special chemical and a very special dynamic bond to the polymer," Evans said. We believe that this combination can be readjusted by adding many other chemicals to adjust the conductivity and mechanical properties. "