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[diaphragm weekly] new technology research and development is in full swing. Where is the future market demand growth point of lithium battery diaphragm?

2019-11-16


沧州明珠股东拟被动减持股份 预计被动减持不超总股本0.66%

[company]Cangzhou Mingzhu shareholders intend to passively reduce their shares, and it is expected that the passive reduction will not exceed 0.66% of the total share capital

On November 11, Cangzhou Mingzhu (002108) announced that the shareholder Juhong (Hong Kong) Co., Ltd. would reduce its holdings of no more than 9396000 shares of the company (accounting for 0.6627% of the total share capital of the company) in the form of centralized bidding transaction due to the passive reduction of holdings, and the cumulative amount of this passive reduction would not exceed 8893055.33 yuan.

It is understood that the reason for the proposed reduction is that Juhong company pledged part of the company's shares held by it to Huaxin International Trust Co., Ltd. because of its equity pledge for the 70million yuan loan of Xinghua pharmaceutical. The Pledged Shares are 23575000 shares, accounting for 1.6626% of the total share capital of the company. Because Xinghua pharmaceutical failed to fulfill its debt repayment obligations in time, this part of the shares were judicially frozen by the Guangzhou court, Among them, 14179000 shares were forcibly sold in the form of centralized bidding transaction from June 5, 2019 to June 26, 2019. As of November 8, 2019, the number of shares of Juhong company that had been judicially frozen by the Guangzhou court was 9396000 shares. Because Xinghua pharmaceutical had not fully resolved the matter of failing to perform its debt repayment obligations when due, some of the frozen shares of Juhong company will continue to be disposed of by the Guangzhou court, The sources of shares are shares obtained before the initial public offering and shares transferred due to equity distribution over the years.

The company's 2019 semi annual report shows that the net profit attributable to shareholders of Listed Companies in the first half of 2019 was 96.8395 million yuan, a decrease of 21.51% over the same period last year. (source: shell digging net)

中国科大构建仿珍珠母层隔膜提升锂电池抗冲击性能

[technology] China University of science and technology builds a mother of Pearl diaphragm to improve the impact resistance of lithium batteries

Recently, the research team of yaohongbin, Ni Yong and Yu Shuhong, professors of the University of science and technology of China, inspired by the high toughness of the nacre, proposed a method to strengthen the impact toughness of polyolefin membranes. By constructing a pearl like coating on the surface of the polyethylene diaphragm, the team effectively maintained the pore structure inside the diaphragm after impact, thus ensuring a uniform lithium ion flow during battery charging and discharging. Compared with the soft pack battery with commercial ceramic diaphragm, the soft pack battery with pearl like diaphragm shows smaller open circuit voltage change, better cycle stability and high safety during impact. The research results were published online in advanced materials under the title of a nacre inspired separator coating for impact tolerant lithium batteries on November 6.

At present, ceramic nano particle coating is widely used to improve the thermal stability of polyolefin membrane and the wettability to electrolyte. However, force analysis shows that the nano particle coating is difficult to effectively resist the impact of localized external forces, which will inevitably lead to uneven lithium ion flow in the battery during charge and discharge, lead to uneven lithium deposition on the electrode, and even lead to the formation of lithium dendrites (as shown in Figure 1a). Based on a deep understanding of the principle of high toughness of mother of pearl layer in nature, the research team constructed an ordered structure of "brick mud" imitating pearl layer on the surface of polyethylene diaphragm. When impacted by external forces, the mother of Pearl like coating can effectively expand the stress area to dissipate the impact stress through the effect of sheet slip, so as to effectively protect the internal pore structure of the diaphragm and maintain the uniform lithium ion flow inside the battery (as shown in Figure 1b).

In order to further confirm the role of nacre inspired diaphragms in the safety of commercial batteries, the research team conducted impact tests on two kinds of soft packed batteries assembled with diaphragms. Compared with the soft pack battery using the commercial nano particle coated diaphragm, the soft pack battery using the imitation nacre diaphragm shows lower instantaneous open circuit voltage change and faster voltage recovery (as shown in Figure 2a, b). The research team also continued to investigate the long cycle performance of the soft pack battery after being impacted twice. The soft pack battery using the mother of pearl coating diaphragm still showed good stability in more than 80 cycles (see Figure 2C). The above research results show that the imitation mother of Pearl diaphragm has a good protective effect on the battery and can effectively reduce many potential safety hazards.

This work puts forward the strategy of building a pearly like toughened diaphragm, and proves its ability to improve the impact resistance of lithium batteries from theoretical simulation and experimental tests, which will open up a new way to improve the safety of lithium batteries in the future. (source: University of science and technology of China)

河北工业大学-加拿大滑铁卢大学Adv. Mater.:低带隙硒化锑半导体改性隔膜助力高性能锂硫电池

[technology]Hebei University of technology - University of Waterloo, Canada adv. mater.: Low band gap antimony selenide semiconductor modified diaphragm helps high performance lithium sulfur battery

With the vigorous development of portable electronic products, electric vehicles, unmanned aircraft and other fields, the research and development of high-energy density energy storage batteries has also attracted market attention. Under the background of limited energy density of lithium-ion batteries, they are cheap, environmentally friendly and have high theoretical specific capacity (1675mahg-1)And high theoretical energy density (2600whkg-1)Lithium sulfur battery is one of the most promising secondary battery systems in chemical energy storage devices. However, at present, the development of lithium sulfur batteries is still hindered by some technical challenges, such as the volume expansion of sulfur during charging and discharging, and the soluble lithium polysulfide intermediate LitwoSx(2<x<8) and elemental sulfur and the final discharge product lithium sulfide (LitwoStwo/LitwoS) The low conductivity seriously reduces the utilization rate of sulfur, electron transmission efficiency and electrochemical reaction rate, thus affecting the cycle life and rate performance of the battery.

? In view of the above problems, the modification of the diaphragm can limit the intermediate lithium polysulfide to the sulfur cathode side as far as possible, reduce its direct contact with the lithium cathode and inhibit the shuttle effect. The current membrane modification materials are mainly carbon materials with high conductivity, nano metal oxygen / sulfide and their related composites. Through the physical and chemical double adsorption of lithium polysulfide, the purpose of inhibiting the shuttle effect of lithium polysulfide can be achieved. However, the slow reaction kinetics of the battery is still one of the problems we face. The introduction of materials with catalytic activity can accelerate the redox reaction rate of lithium polysulfide, effectively shorten the existence time of the intermediate lithium polysulfide, avoid serious capacity decay, and improve the electrochemical performance. In this study, antimony selenide semiconductor with low bandgap selenium deficiency was introduced into the modification of diaphragm for the first time. On the one hand, the electronic structure is regulated through semiconductor defect engineering to further enhance its conductivity. On the other hand, the chemical anchored lithium polysulfide and its electrocatalysis performance are enhanced through the design of defects and material phase composition, so as to effectively inhibit the shuttle effect and accelerate the kinetic conversion of lithium polysulfide.

Recently, academician Chen Zhongwei of the University of Waterloo, Canada, Associate Professor Zhang Yongguang of Hebei University of technology, and Associate Professor Li Jingde (co corresponding author) modified the selenium rich vacancy (VSe)Sb oftwoSe3-x/RGO composite microspheres were introduced into lithium sulfur batteries for the first time. This low band gap (1.0-1.2ev) antimony selenide semiconductor has strong conductivity, low cost, easy to control defects, and then enhance its conductivity. It has great application potential in the improvement of lithium sulfur battery system. In this paper, a complete microsphere structure was constructed by spray drying process to ensure long-range charge transfer, followed by chemical reduction and rapid thermal shocktwoSe3-x/Introduction of a large amount of V into RGO complexSe。 The semiconductor defect engineering not only significantly improves its conductivity and strengthens the chemical adsorption of polysulfides, but also greatly promotes the kinetic conversion process of catalytic polysulfides. SbtwoSe3-x/The introduction of RGO modified diaphragm effectively alleviates the "shuttle effect" caused by polysulfides, so as to achieve efficient and lasting electrochemical behavior of sulfur. With sbtwoSe3-x/The lithium sulfur battery with RGO modified diaphragm shows excellent rate performance (8.0c), good cycle stability (decay capacity rate is only 0.027% per cycle), and high sulfur load (8.1mgcm-2)It still has 7.46mahcm under-2Area capacity of. This work introduces selenium deficient semiconductor modified diaphragm for the first time, opens up a new design defect engineering method, and provides new insights for the realization of high-performance lithium sulfur batteries.

In this study, Sb rich in selenium deficiency was developed through a simple spray drying and defect engineeringtwoSe3-x/RGO semiconductor based material microspheres, as a modified diaphragm material, can effectively inhibit the "shuttle effect" and obtain excellent electrochemical performance of lithium sulfur batteries. This multi-level structure can be used as a conductive framework for electron / ion transport, while providing rich active interfaces to limit and transform polysulfides. In addition, the material has stronger conductivity, polysulfide adsorption capacity and catalytic activity, establishes a barrier to prevent the shuttle of polysulfides, and promotes the chemical kinetic process of lithium sulfur battery. Thanks to these advantages, the developed has sbtwoSe3-x/The lithium sulfur battery with RGO modified diaphragm showed good rate performance up to 8.0c, and the capacity attenuation per cycle was only 0.027% at 1.0c. This study has important guidance and reference for the development of modified membranes with dual functions of adsorption and catalysis, as well as high-performance lithium sulfur batteries. (source: energy scholar)

[think tank circle] where is the future market demand growth point of lithium diaphragm?

At present, the growth rate of consumer lithium batteries dominated by smart phones is slowing down, and due to the four consecutive declines in the sales of new energy vehicles, the market demand for automotive power batteries is not optimistic. The industry expects that new wearable devices, smart homes, electric bicycles, grid energy storage and other fields may become new market demand growth points for lithium batteries, and in the face of intensified competition in the field of power batteries, Some diaphragm and other raw material enterprises are trying to seek new market demand growth points.

In addition, relevant statistics show that in the field of power batteries, although the domestic market demand for lithium battery diaphragms accounts for more than 50% of the global power market demand, the gap between the total demand for diaphragms in the domestic and foreign power battery markets has been narrowing in recent years. The growth of the overseas power market is expected, and domestic head diaphragm manufacturers may benefit.

Article source:Battery net

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