A Chinese university team breaks through the limits of lithium-ion batteries.

Hangzhou, March 19 (China News Service) -- According to a report from Westlake University on the 19th, a research team at the university has innovatively developed a "shuttle-coupled electrolyte," successfully overcoming the key bottleneck of short cycle life in negative electrode-less lithium metal batteries, and taking a solid step towards the large-scale mass production of high-energy-density batteries.

A team led by Wang Jianhui from the College of Engineering at Westlake University published a paper titled "Planar Li Deposition and Dissolution Enable Practical Anode-Free Pouch Cells" online in the journal Nature on the 18th (Beijing time).

Negative electrode-free lithium metal batteries are considered the "holy grail" of the lithium battery field due to their advantages of high energy density, low cost, and easy assembly, but their fatal flaw of extremely short cycle life has kept them in the laboratory prototype stage for a long time.

Traditional negative electrode-less batteries do not have an additional lithium source for replenishment. During charging, lithium ions are prone to uneven deposition on the surface of the copper foil current collector, forming dendrites, which triggers side reactions and produces "dead lithium," leading to rapid battery degradation. Existing products have a cycle life of only 10 to 150 times, far lower than the more than 800 times of commercial lithium-ion batteries.

After five and a half years of research, Wang Jianhui's team developed a "shuttle-coupled electrolyte" that can achieve highly synchronous planar deposition and dissolution of lithium metal, fundamentally solving the dendrite problem.

According to Wang Jianhui, this electrolyte can form a uniform, sub-nanometer-thick boron-fluorine polymer SEI film on the negative electrode surface. This "adaptive skin" allows lithium ions to enter and exit uniformly, while adapting to the expansion and contraction of lithium metal without breaking. More importantly, this SEI film is formed through the synergistic evolution of the positive and negative electrodes across space, breaking through the traditional electrolyte interface chemistry theory.

Experimental data shows that the negative electrode-free lithium metal pouch battery developed by the team achieves an energy density of 508Wh/kg and 1668Wh/L without current collector modification or external lithium replenishment. It maintains stable cycling for over 350 cycles at 80% depth of discharge, supports continuous discharge at 2650W/kg for over 130 seconds, and operates over a wide temperature range of -40℃ to 60℃. The unit watt-hour cost is 15% to 25% lower than that of commercial graphite-based lithium-ion batteries. Mass spectrometry titration analysis confirms that the percentage of "dead lithium" after long-cycle operation is only 3.5%, far lower than similar advanced electrolytes.

The proposed "planar lithium deposition and dissolution mechanism" overcomes the inherent instability of hostless metal electrode structures, paving a new path for the development of high-performance metal electrodes beyond the "embedding chemistry" mechanism. This breakthrough is expected to drive the development of flying cars, electric vehicles, AR/VR glasses, and other fields, enabling scenarios such as daily intercity flights for flying cars and doubling the range of electric vehicles to move from concept to reality. (End)