High Energy Density Nano Solid Metal Lithium Battery and Its Key Materials

Fig. 1. A schematic diagram of(a) deposition process and(b) deposition mechanism of metallic lithium on curved graphite spheres.

Figure 2. (a) A schematic diagram of the discharge curve and deposition of graphed carbon fiber. (b) The original material and(c) after discharge to 0V,(d) deposition of 2mAhcm? After 2,(E) deposit 8mAhcm? After 2,(f) dissolves 4mAhcm? 2 The surface morphology of the electrode when charged to 1V with(g).

Figure 3. (a) Preparation(top) and lithium deposition(bottom) of ipn-PEA electrolytes. (b) Modular diagram of ipn-PEA electrolytes. (c) Li | ipn-PEA electrolyte | LFP soft pack battery cut voltage photo. The LED device can be lit before(E) and after(f) the flexible battery bending test.

With the support of the Ministry of Science and Technology, the State Council of Natural Science and Technology and the Chinese Academy of Sciences, the China National Science and Technology Foundation have made great efforts to develop high energy density nano-solid lithium metal batteries to solve the challenges of recycling and safety. Guoyuguo, a researcher at the Key Laboratory of Molecular Nano Structures and Nanotechnology of the Institute of Chemistry of the Chinese Academy of Sciences, made a series of advances in the research of metal lithium negative electrode, solid electrolyte, and a solid battery.

In recent years, researchers in this group have long devoted themselves to the study of the negative electrode of metal lithium. In the previous research work, in order to solve the problem of uneven dissolution and deposition(ie dendrite) of the negative electrode of metal lithium during charging and discharging, they proposed the use of three-dimensional nanocrystals to guide the uniform deposition and dissolution of metal lithium inside the three-dimensional electrode. The control of metallic lithium dendrites was successfully achieved(Nat.Comun. , 2015, 6,8058). The researchers proposed and developed an in-situ treatment technology that successfully formed a lithium electrolyte phosphate solid membrane with Gaoyangshi modulus and rapid lithium ion transport capability on the surface of metallic lithium, which effectively reduced the side reaction between metallic lithium and electrolyte. The growth of lithium dendrites(Adv.Mater. , 2016, 28, 1853).

In order to further solve the problem of low utilization of metal lithium negative poles, the researchers proposed a highly efficient and stable "lithium storage room" concept(Figure 1) based on the structural advantages of graphite carbon materials, and grew onion on the three-dimensional conductive skeleton., graphed spherical carbon particles, The uniform regulation of the metal lithium/electrolyte interface is achieved, the growth of metallic lithium dendrites on the carbon spherical surface is effectively controlled, and the utilization rate of lithium is greatly increased. Under the condition that the negative electrode capacity is only 5 % excessive, the battery can still stabilize the cycle for a long time. The results of this study are recently published. Published in J.Am.Chem.Soc. (2017, 139,5916).

In order to solve the problem of dendrite growth and poor cycle stability in high-capacity lithium metal anodes, the researchers used electrochemically active graphitized carbon fibers as multifunctional three-dimensional current collectors to obtain metals with a surface area of up to 8 mAhcm-2 and no dendrites. Lithium negative electrode. Since graphitized carbon fiber can reduce local current density and alleviate volume change, the anode exhibits high coulombic efficiency, low voltage polarization and long cycle life during cycling. Related results were recently published in Adv. Mater. (2017, 29, 1700389) ) on.

In the early research work on electrolytes for metal lithium batteries, the irreversible degradation of SEI formed spontaneously on the surface of metal lithium during the cycle process exists. The task group designed a mixed electrolyte system of ether electrolytes plus Ionic liquids. Improved deposition behavior and cyclic stability of metal lithium negative electrode(Adv.Sci. , 2017, 4,1600400); The researchers proposed a functional electrolyte additive containing Al colloidal particles. By adding AlCl3 to the electrolyte, they succeeded in forming a uniform, stable, and compact SEI membrane on the surface of metallic lithium in situ, stabilizing the interface of metallic lithium/electrolyte.(NanoEnergy, 2017, 36,411).

To improve battery safety and further solve the problem of lithium dendrites in liquid electrolytes, the researchers designed and constructed a type of two-function interpenetrating network structure poly(ether-acrylate) solid electrolyte(Fig. 3). The solid electrolyte(ipn-PEA) sets a high mechanical strength(about 12 GPa) and a high chamber temperature ion conductivity(0.22 mScm?). 1) In one, the deposition/precipitation of lithium is balanced. Due to the dual effect of reducing interface resistance and accelerating lithium ion transmission, ipn-PEA electrolytes effectively inhibit the growth of lithium dendrites and reshape the feasibility of room temperature solid lithium metal batteries(J.Am.Chem.Soc., 2016, 138, 15825).

In view of the task group's leading research on solid metal lithium batteries, the researchers were invited by the editor-in-chief of ACSENERGYLET to write an outlook paper on the research and development prospects of solid metal lithium batteries(ACSENERGYLET. , 2017, 2, 1385), at the same time, he was invited to write a summary article on advanced carbon materials in the lithium negative electrode of metal(Adv.Energy Mater. , 2017, DOI: 10.1002 / aenm. 2017 00530). In addition, at the invitation of the Adv.Sci.Journal, the team also collaborated with Zhang Qiang, an associate professor at Tsinghua University, to write an overview paper on lithium electrochemical behavior and electrode design strategies(Adv.Sci.2017, 4,1600445).

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