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“Picture” of pre lithification of power batteries

"Picture" of pre lithification of power batteries

The market's demand for high-end power and energy storage batteries is expanding, and the pursuit of higher energy density is driving power battery manufacturers to apply new technologies, constantly challenging the "ceiling" of the industry. The product advantages brought about by new technological changes may become a new starting point for battery companies to compete for discourse power in the supply chain.

In terms of electrodes, as a "container" for storing lithium ions, selecting new electrode materials with higher capacity is a direct means of breaking the energy "ceiling". In addition to working hard on the materials of the "container" itself, pre lithification of the electrodes is an effective way to directly improve the overall capacity and energy density of the battery.

However, during the "large-scale production expansion" period, the mass production of power batteries is mainly based on the application of safe and industrially mature materials, and the industrialization of new electrode materials is still in its infancy. As production expansion is nearing its end, it is more feasible to promote the implementation of pre lithification technology based on current manufacturing processes.

Pre lithium technology Positive electrode easy to negative electrode

During the first charging process of a lithium battery, the electrolyte will reduce and decompose on the surface of the negative electrode, forming a solid electrolyte phase interface (SEI) film, consuming lithium ions, resulting in low initial cycle and coulomb efficiency (ICE), reducing the capacity and energy density of the lithium battery. Pre lithification is achieved by adding lithium to reduce the loss of lithium ions, achieving the effect of improving battery capacity and energy density.

In terms of industrialization, lithium supplementation for negative electrodes is direct but difficult. Currently, the main route is to supplement reducing lithium, which can be achieved through lithium foil, lithium powder, or additives.

The difficulty lies in the difficulty of the lithium supplement process for the negative electrode. The existing electrode preparation environment is humid, while reducing lithium has high reactivity, which involves stabilizing and surface modifying the reducing lithium. In addition to the difficulty of the process, if the supplementary reducing lithium does not play the role of pre lithification, it will be converted into dead lithium, leading to lithium evolution.

The positive electrode achieves "indirect lithium supplementation" by adding lithium supplements, which is more compatible with existing lithium battery manufacturing processes. By adding a lithium supplement, lithium ions are pushed to the negative electrode during charging. The ideal positive electrode lithium supplement should have the characteristics of high specific energy, stability, and compatibility with the battery material system.

Successive landing of patents

As a new technology "race track" to achieve a further increase in battery energy density, power battery companies and material companies are "ambitious" for pre lithium technology, and have successively launched patent layouts around pre lithium technology.

From the perspective of the patent layout of relevant enterprises, various enterprises have explored the technology of pre lithification of positive electrodes and negative electrodes. However, from the perspective of feasibility, the industrialization of positive electrode lithium supplements is less difficult to implement, and further industrialization can be promoted around relevant patents.

A patent issued by Ningde Times in 2021 included a synthesis method for lithium silicon alloy lithium replenishing agents. The addition location of lithium replenishing agents covers the surface of the positive electrode, the current collector, and between the positive electrodes, which can significantly improve the battery's initial efficiency (from less than 80% to nearly 100%), cycle life, and effectively inhibit battery expansion.

In 2021, Guoxuan High Tech also issued two patents on positive electrode lithium supplement, namely graphene oxide cobalt lithium oxide positive electrode lithium supplement and low-cost sol gel process positive electrode lithium supplement.

In 2020, German Nano released a patent for the synthesis method of lithium ferrite as a positive electrode lithium supplement (lithium rich). In addition, German Nanometer has also studied the method of magnetron sputtering the positive electrode lithium supplement agent to the positive electrode precursor ball milling device, and then calcining the precursor to obtain the positive electrode material.

Industrialization of lithium supplements starts

In terms of industrialization, positive electrode lithium supplements have shown great application potential, and enterprises have started on the road to industrialization of positive electrode lithium supplements.

On February 26th, the annual production of 20000 tons of lithium supplement agent project (Phase I) of German Nanometer subsidiary German Chuangyu was officially put into production in Qujing, Yunnan. It is understood that this project is currently the first positive electrode lithium supplement project in the world to achieve mass production. German Nano stated that in the future, it will accelerate the construction process of the second phase of the Qujing Chuangjie Lithium Supplement Project with an annual output of 20000 tons and the Chengdu Chuangjie Lithium Supplement Project with an annual output of 5000 tons.

In addition, after the opening of the new year of Yanyi New Material, it was disclosed that the independently developed LNO and LFO positive electrode lithium supplements had been shipped in mass production in 2022, and had been recognized by leading international and domestic customers. The product's prying cell capacity was equivalent to about 5GWh. Yanyi Materials has arranged a new lithium supplement project and a research institute project in Wuxi, and will add about 10000 tons of lithium supplement capacity upon completion of the project.

With the gradual expansion of silicon based negative electrodes and the demand for lithium supplementation for high-end power and energy storage batteries, pre lithification is gradually becoming a major development direction for lithium batteries.

Currently, the pre lithification technology in the industry is still in the exploration stage, but with the mass production of lithium supplements, the application of pre lithification is close at hand. According to relevant forecasts, by 2025, the lithium supplement market may exceed 10 billion yuan. The race around the lithium supplement, a new segment of the track, has already begun. Whether the starters continue to lead, or whether the latecomers have made a surprising move to top, remains unknown.

Post time: Apr-28-2023