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[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

/pdf/high-performance-lithium-battery-anodes-using-silicon-58e1j6kr4f.pdf

High-performance lithium battery anodes using silicon nanowires

Li-ion battery materials: present and future

Research Development on Sodium-Ion Batteries

With the increasing demand for efficient and economic energy storage, Li-S batteries have become attractive candidates for the next-generation high-energy rechargeable Li batteries because of their high theoretical energy density and cost effectiveness. Starting from a brief history of Li-S batteries, this Review introduces the electrochemistry of Li-S batteries, and discusses issues resulting from the electrochemistry, such as the electroactivity and the polysulfide dissolution. To address these critical issues, recent advances in Li-S batteries are summarized, including the S cathode, Li anode, electrolyte, and new designs of Li-S batteries with a metallic Li-free anode. Constructing S molecules confined in the conductive microporous carbon materials to improve the cyclability of Li-S batteries serves as a prospective strategy for the industry in the future.

Lithium–Sulfur Batteries: Electrochemistry, Materials, and Prospects

One of the greatest challenges for our society is providing powerful electrochemical energy conversion and storage devices. Rechargeable lithium-ion batteries and fuel cells are amongst the most promising candidates in terms of energy densities and power densities. Nanostructured materials are currently of interest for such devices because of their high surface area, novel size effects, significantly enhanced kinetics, and so on. This Progress Report describes some recent developments in nanostructured anode and cathode materials for lithium-ion batteries, addressing the benefits of nanometer-size effects, the disadvantages of 'nano', and strategies to solve these issues such as nano/micro hierarchical structures and surface coatings, as well as developments in the discovery of nanostructured Pt-based electrocatalysts for direct methanol fuel cells (DMFCs). Approaches to lowering the cost of Pt catalysts include the use of i) novel nanostructures of Pt, ii) new cost-effective synthesis routes, iii) binary or multiple catalysts, and iv) new catalyst supports.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.200800627

Nanostructured Materials for Electrochemical Energy Conversion and Storage Devices

The lithium–sulfur battery holds a high theoretical energy density, 4–5 times that of today’s lithium-ion batteries, yet its applications have been hindered by poor electronic conductivity of the sulfur cathode and, most importantly, the rapid fading of its capacity due to the formation of soluble polysulfide intermediates (Li2Sn, n = 4–8). Despite numerous efforts concerning this issue, combatting sulfur loss remains one of the greatest challenges. Here we show that this problem can be effectively diminished by controlling the sulfur as smaller allotropes. Metastable small sulfur molecules of S2–4 were synthesized in the confined space of a conductive microporous carbon matrix. The confined S2–4 as a new cathode material can totally avoid the unfavorable transition between the commonly used large S8 and S42–. Li–S batteries based on this concept exhibit unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior rate capability, which promise a practicable bat...

Smaller sulfur molecules promise better lithium-sulfur batteries.

Lithium metal is one of the most attractive anode materials for electrochemical energy storage. However, the growth of Li dendrites during electrochemical deposition, which leads to a low Coulombic efficiency and safety concerns, has long hindered the application of rechargeable Li-metal batteries. Here we show that a 3D current collector with a submicron skeleton and high electroactive surface area can significantly improve the electrochemical deposition behaviour of Li. Li anode is accommodated in the 3D structure without uncontrollable Li dendrites. With the growth of Li dendrites being effectively suppressed, the Li anode in the 3D current collector can run for 600 h without short circuit and exhibits low voltage hysteresis. The exceptional electrochemical performance of the Li-metal anode in the 3D current collector highlights the importance of rational design of current collectors and reveals a new avenue for developing Li anodes with a long lifespan.

/pdf/accommodating-lithium-into-3d-current-collectors-with-a-576j4y29sc.pdf

Accommodating lithium into 3D current collectors with a submicron skeleton towards long-life lithium metal anodes.

A Li3PO4 solid electrolyte interphase (SEI) layer is demonstrated to be stable in the organic electrolyte, even during the Li deposition/dissolution process. Thus, the Li-conducting Li3PO4 SEI layer with a high Young's modulus can effectively reduce side reactions between Li metal and the electrolyte and can restrain Li dendrite growth in lithium-metal batteries during cycling.

Yu-Guo Guo

Papers

Lithium–Sulfur Batteries: Electrochemistry, Materials, and Prospects

Nanostructured Materials for Electrochemical Energy Conversion and Storage Devices

Smaller sulfur molecules promise better lithium-sulfur batteries.

Accommodating lithium into 3D current collectors with a submicron skeleton towards long-life lithium metal anodes.

An Artificial Solid Electrolyte Interphase Layer for Stable Lithium Metal Anodes