As the name suggests, solid-state lithium-ion batteries have no liquid electrolyte in them, but are replaced by polymer-based solid-state electrolytes (or coated on the surface of the diaphragm). The migration of lithium ions mainly depends on solid-state diffusion.
Most of the lithium-ion batteries currently on the market are called liquid lithium-ion batteries, which contain liquid electrolyte, mainly made of positive electrode, separator, negative electrode, and then filled with electrolyte. Lithium ions migrate back and forth between the positive and negative electrodes through the electrolyte.
Most of the lithium-ion batteries currently on the market are called liquid lithium-ion batteries, which contain liquid electrolyte, mainly made of positive electrode, separator, negative electrode, and then filled with electrolyte. Lithium ions migrate back and forth between the positive and negative electrodes through the electrolyte.
1. The weight of a cell, the electrolyte may account for about 20-30%. (If liquid electrolyte is not used, the weight of the battery will be reduced a lot, and the energy density of the battery will be increased accordingly)
2) The electrolyte is extremely flammable, and the poor safety of traditional lithium-ion batteries has a lot to do with liquid electrolytes.
3) The electrolyte is unstable under high voltage, and is easily oxidized and decomposed into gas, resulting in deterioration of the cell and even danger.
4) The electrolyte composition is lithium hexafluorophosphate, some ester organic compounds, and a small amount of other additives, which have certain corrosiveness and environmental toxicity.
Based on the above points, the energy density of all-solid-state lithium-ion batteries will be higher, the safety will be greatly improved, it can withstand higher voltages, the overcharge resistance will also be improved, and there is basically no environmental toxicity.
But are there no disadvantages to all-solid-state lithium-ion batteries? the answer is negative. The disadvantages of solid-state lithium-ion batteries are as follows:
#1-The problem of low conductivity:
The conductivity is low, that is, the efficiency of electron passing is low, and the interface impedance is large, that is, the connection between the positive and negative electrodes and the diaphragm has the problem of high resistance and poor contact. The best solution at present is to find a suitable electrolyte, so that its structure can not only allow the smooth passage of lithium ions, but also solve the problem of contact, but the problem is that the cost of this electrolyte is quite high (with existing The technology to manufacture solid-state batteries that power mobile phones costs as much as 60,000 yuan), so it has not yet been widely commercialized.
#2-Interface impedance and stability issues：
The solid-state diffusion rate of lithium ions is much slower than that in solution, so it can only be used in devices with small currents, and the long-awaited fast charging is even more difficult to achieve. Another disadvantage is that the manufacturing technology is complex and the cost is high.
Due to the high energy density of the all-solid-state lithium-ion battery, the battery life will definitely go to a higher level, but it cannot be quickly charged and discharged, and it is still in the experimental stage. The safety will undoubtedly be greatly improved, and the loop performance will not be very good.
However, the prospect of solid-state lithium-ion batteries is very good, and large-scale commercial use will certainly be achieved in the future with technological breakthroughs.
