Which new energy products have begun to use silicon-based anode materials?

As we all know, the mileage of electric vehicles has always been a pain point of urgent concern for consumers.

At present, the capacity of graphite anode widely used in commercial lithium batteries is about 360mAh/g, which is very close to its theoretical specific capacity (372mAh/g).

Performance comparison of carbon materials and silicon materials

Development status of silicon-based anode technology

As a negative electrode material, silicon will produce a great volume change.

In the silicon-carbon composite system, carbon can improve the conductivity of the material, buffer the volume change of silicon, avoid the agglomeration of silicon particles, etc.

Common core-shell structure

In addition, the silicon-carbon anode has another problem that attracts attention.

In summary, the silicon-carbon anode has a high capacity, but the volume expansion and other problems lead to a slightly lower life.

The status quo of industrialization of silicon-based anode

The development of silicon-carbon anode materials in China is at an early stage.

According to statistics, China's shipments of silicon-carbon anode materials will be 9 million tons in 2020, accounting for only about 2% of the shipments of anode materials

The status quo of the industrialization of silicon carbon anodes by domestic anode material giants

Application status of silicon-based anode

In addition to its application in ternary batteries, in January 2021, Guoxuan High-Tech officially released a soft-packed lithium iron phosphate battery with an energy density of 210Wh/kg, and claimed that it had successfully applied silicon anode materials in the lithium iron phosphate chemical system for the first time
.

At present, due to the high price of silicon carbon anode, it is mainly used in high-end models
.
Since the beginning of this year, as the competition of car companies in the high-end market has intensified, models equipped with silicon-carbon anode batteries have also begun to emerge
.

01 Tesla: From doping silicon to directly using silicon anode

The cylindrical battery structure that Tesla has always used has a better suppression effect on the volume expansion of the silicon carbon anode.
Since ModelS and ModelX a few years ago, Tesla has already doped silicon materials in the graphite anode.
Very few ingredients
.
In the Model 3 stage, the proportion of silicon in the 21700 battery used by Tesla has been increased again, and its energy density has increased by about 20% compared with the previous generation 18650 battery, reaching 300Wh/kg.
The current cruising range of the Model 3 is about 500-600 kilometers
.

On "Battery Day" on September 22, 2020, Tesla clearly plans to use silicon anodes in the future.
It plans to use metallurgical silicon as a raw material to improve the performance of silicon anodes through ion-conducting polymer coating and special adhesive mixing
.

Tesla's generations of cylindrical batteries

02

GAC Aeon-Sponge Silicon Negative Sheet Battery Technology

GAC Aian announced its self-developed sponge silicon anode battery technology this year.
This technology includes "nano composite silicon technology", "self-healing binder technology", "gradient composite coating technology", etc.
, so that the silicon anode film inside the battery is like The sponge is as soft and elastic, so that the expansion and contraction of silicon during charging and discharging are limited and buffered, and it will not be broken
.
At the same time, it also acts like a sponge to absorb water, allowing the silicon anode to take advantage of its large capacity and store more energy
.

Through this technology, the volume of lithium-ion battery cells can be reduced by 20%, and the weight can be reduced by 14%; in the future, the volume and weight will be further reduced and reduced by more than half
.
This technology also has a significant effect on extending battery life and improving the reliability of lithium-ion batteries
.
GAC AIONLX, which is equipped with sponge silicon negative plate battery technology, can achieve a cruising range of more than 1,000km, and is expected to be put into production within this year
.

03

NIO——Silicon Carbon Anode + Semi-Solid Electrolyte + High Nickel Cathode

NIO announced on the NIO Day held in January that it expects to deliver 150kWh battery packs in 2022, using in-situ solid-liquid electrolytes, inorganic pre-lithiated silicon carbon anodes, and nano-scale coated ultra-high nickel cathodes.
The energy density of the single unit can be Up to 360Wh/kg, Weilai ET7 will be equipped with this battery
.

NIO 150kWh battery pack

04

Zhihad Automobile-"Silicon Doping and Lithium Supplement" Technology

In January, SAIC Motor, Pudong New Area, and Alibaba’s Zhiji Auto released their first model, the Zhiji L7.
Its 118kWh battery is a high-profile version that uses the "silicon doped lithium supplement" technology in cooperation with CATL, which can achieve single With an energy density of 300Wh/kg, the NEDC battery life will be increased to 1000km, and it will have 200,000 kilometers of zero attenuation and "never spontaneous combustion" characteristics.
The high-end version is planned to be launched in 2022
.

Zhiye Automobile and Ningde Times

Summarize

The current commercial silicon-based anode materials mainly include carbon-coated silicon oxide, nano silicon carbon, amorphous silicon alloys, and silicon nanowires.
Among them, carbon-coated silicon oxide and nano silicon carbon have the highest degree of commercialization
.
At present, various battery factories and car factories are already using silicon on a large scale in the design of next-generation batteries, and silicon-based anode material products are bound to show a trend of high growth.
The lithium battery industry is gradually ushering in an era of full-scale explosion of silicon-based anodes
.