New breakthrough in nanometer ultra-capacity lithium battery -Lithium - Ion Battery Equipment
Electric vehicles will become an important green means of transportation in the future, and there is an urgent need to develop new high-capacity, high-stability and high-safety lithium batteries. Scientists are also constantly trying various methods to improve the performance of lithium batteries, among which nanometerization is a common method to improve the electrochemical performance of materials, especially for low-conductivity materials such as lithium iron phosphate, which have a significant improvement effect. The advantage of nanoscale is that the transport path of lithium ions is shortened and better rate performance can be obtained. Compared with bulk materials, the disadvantages of nanoscale include the reduction of the binding energy of lithium on the surface and the interfacial atoms, which will lead to the loss of capacity and the reduction of voltage; the large specific surface area after nanoscale will bring more active sites, and a large number of The contact between the active site and the electrolyte will also become an important factor affecting the charging and discharging stability of lithium batteries; the reduction of tap density and energy density brought about by nanometerization is a problem that cannot be ignored in industrial production.(Lithium - Ion Battery Equipment)
(A) The charge-discharge curves of 40nm LiFePO4 ordinary and supercapacity-coated carbon; (B) the charge-discharge curves of 83nm LiFePO4 ordinary and supercapacity-coated carbon; (C) The exposed LiFePO4 interface; (D) After reconstruction LiFePO4 interface (N stands for ordinary carbon-encapsulation method, E for supercapacity carbon-encapsulation method)
In order to carry forward the advantages of nanotechnology and overcome its shortcomings, after three years of hard work, Professor Pan Feng's research group from the School of New Materials, Peking University Shenzhen Graduate School finally made an important breakthrough. They cleverly covered the surface of the nanolithium iron phosphate with a shell that can coordinate reaction with the interface (the C-O-Fe chemical bond generated on the surface of the lithium iron phosphate), which not only improved the binding energy of the surface lithium ions, but also appeared additional the lithium ion storage site. Using the reconstituted nanolithium iron phosphate material when the average particle size is 42nm, the material capacity can reach 207mAhg-1, which exceeds 21% of its theoretical capacity (170mAhg-1), so it is a new type of ultra-capacity nano-positive electrode Material. The material has good stability and can still maintain 99% of the capacity after 1000 cycles at 10 °C.
(A) The effect of LiFePO4 particle size on the capacity after reconstitution (black and blue dots are theoretical values, red dots are experimental values); (B-D) Lithium manganese phosphate, lithium manganese phosphate and lithium cobalt phosphate are carbon-coated and ultra-thin The charge-discharge curve of capacity package carbon
Through the combination of quantum chemical theoretical calculations and experiments, the team revealed the mechanism of nanometer supercapacity energy storage. This discovery is of great significance for the development of new nanometer energy storage materials. People can reconstruct the interface shell by designing coordination groups, not only It can realize supercapacity energy storage, and can also improve the stability of nanomaterial applications. The work was published in NanoLetters, an excellent international journal in the field of materials recently (DOI: 10.1021/acs.nanolett.7b02315, impact factor 12.7, one of the journals of the Nature Publishing Index). Under the guidance of Professor Pan Feng, the work was completed by Dr. Duan Yandong, Dr. Zhang Bingkai, Dr. Zheng Jiaxin and 2015 doctoral student Hu Jiangtao. Important collaborators of this work include Professors Khalil Amine and Yang Ren of Argonne National Laboratory, Professor Lin-Wang Wang and Wanli Yang of Berkeley National Laboratory, and Professor Chong-Min Wang of Pacific Northwest National Laboratory. This work was supported by the National New Energy Vehicle (Power Lithium Battery) Technology Innovation Project, the Guangdong Provincial Science and Technology Innovation Team Project, the Guangdong Provincial Natural Science Foundation, the Shenzhen Science and Technology Innovation Committee Fund, the US Department of Energy and the Shenzhen National Supercomputing Center. .
(A) The charge-discharge curves of 40nm LiFePO4 ordinary and supercapacity-coated carbon; (B) the charge-discharge curves of 83nm LiFePO4 ordinary and supercapacity-coated carbon; (C) The exposed LiFePO4 interface; (D) After reconstruction LiFePO4 interface (N stands for ordinary carbon-encapsulation method, E for supercapacity carbon-encapsulation method)
In order to carry forward the advantages of nanotechnology and overcome its shortcomings, after three years of hard work, Professor Pan Feng's research group from the School of New Materials, Peking University Shenzhen Graduate School finally made an important breakthrough. They cleverly covered the surface of the nanolithium iron phosphate with a shell that can coordinate reaction with the interface (the C-O-Fe chemical bond generated on the surface of the lithium iron phosphate), which not only improved the binding energy of the surface lithium ions, but also appeared additional the lithium ion storage site. Using the reconstituted nanolithium iron phosphate material when the average particle size is 42nm, the material capacity can reach 207mAhg-1, which exceeds 21% of its theoretical capacity (170mAhg-1), so it is a new type of ultra-capacity nano-positive electrode Material. The material has good stability and can still maintain 99% of the capacity after 1000 cycles at 10 °C.
(A) The effect of LiFePO4 particle size on the capacity after reconstitution (black and blue dots are theoretical values, red dots are experimental values); (B-D) Lithium manganese phosphate, lithium manganese phosphate and lithium cobalt phosphate are carbon-coated and ultra-thin The charge-discharge curve of capacity package carbon
Through the combination of quantum chemical theoretical calculations and experiments, the team revealed the mechanism of nanometer supercapacity energy storage. This discovery is of great significance for the development of new nanometer energy storage materials. People can reconstruct the interface shell by designing coordination groups, not only It can realize supercapacity energy storage, and can also improve the stability of nanomaterial applications. The work was published in NanoLetters, an excellent international journal in the field of materials recently (DOI: 10.1021/acs.nanolett.7b02315, impact factor 12.7, one of the journals of the Nature Publishing Index). Under the guidance of Professor Pan Feng, the work was completed by Dr. Duan Yandong, Dr. Zhang Bingkai, Dr. Zheng Jiaxin and 2015 doctoral student Hu Jiangtao. Important collaborators of this work include Professors Khalil Amine and Yang Ren of Argonne National Laboratory, Professor Lin-Wang Wang and Wanli Yang of Berkeley National Laboratory, and Professor Chong-Min Wang of Pacific Northwest National Laboratory. This work was supported by the National New Energy Vehicle (Power Lithium Battery) Technology Innovation Project, the Guangdong Provincial Science and Technology Innovation Team Project, the Guangdong Provincial Natural Science Foundation, the Shenzhen Science and Technology Innovation Committee Fund, the US Department of Energy and the Shenzhen National Supercomputing Center. .
