(TMTPOST)—Samsung SDI has recently announced its plans to start mass production of solid-state batteries by 2027. The company has already built a trial production line for solid-state batteries with an energy density of 900Wh/L and is currently producing prototype samples.

PowerCo SE, a subsidiary of Volkswagen, announced the results of its collaboration with QuantumScape in conducting over 1000 cycles of charge and discharge tests on solid-state batteries. The battery maintained a capacity of 95%, with no significant degradation after over 500,000 kilometers, demonstrating its excellent cycling life.

Chinese companies are making rapid progress in the commercialization of semi-solid-state batteries. In December 2023, NIO ET7 equipped with semi-solid-state batteries achieved a range of over 1,000 kilometers in endurance testing. In 2024, Dongfeng, NIO, and SAIC will launch models equipped with semi-solid-state batteries, achieving mass production of semi-solid-state batteries for vehicles.

The solid-state battery sector has soared in the stock market, with the sector's stock performance rising by 19.29% since February 6, outperforming the stock market during the same period.

Solid-state batteries, unlike liquid lithium batteries, use solid electrolytes instead of liquid electrolytes and separators. Semi-solid-state batteries utilize a solid-liquid hybrid electrolyte while retaining the separator.

The working principle of solid-state batteries is similar to that of liquid lithium batteries, involving the insertion and extraction of lithium ions between positive and negative electrodes. During charging, lithium ions migrate from the positive electrode through the solid-state electrolyte to the negative electrode, where they combine with electrons flowing from the external circuit to form lithium atoms.

Compared to liquid lithium batteries, solid-state batteries offer significant advantages in energy density and safety. In terms of energy density, while the energy density of liquid lithium batteries has approached the upper limit of 350Wh/kg, solid-state batteries can achieve an energy density of over 500Wh/kg by using high-capacity positive and negative electrode materials.

In terms of safety, traditional liquid lithium batteries may experience lithium dendrite growth on the negative electrode under high current conditions, puncturing the separator and leading to internal short circuits. Additionally, electrolytes are prone to side reactions at high temperatures, posing risks of explosion or combustion. Solid-state electrolytes have low chemical activity and high-temperature resistance, effectively inhibiting lithium dendrite growth and ensuring high safety.

Furthermore, solid-state batteries eliminate the drawbacks of reduced electrolyte flowability in low-temperature environments, enabling stable operation in cold conditions. Additionally, by eliminating the electrolyte and separator, the distance between the positive and negative electrodes is shorter in solid-state batteries, leading to smaller battery volumes for the same capacity.