Li-ion battery materials: present and future

Many metal–insulator–metal systems show electrically induced resistive switching effects and have therefore been proposed as the basis for future non-volatile memories. They combine the advantages of Flash and DRAM (dynamic random access memories) while avoiding their drawbacks, and they might be highly scalable. Here we propose a coarse-grained classification into primarily thermal, electrical or ion-migration-induced switching mechanisms. The ion-migration effects are coupled to redox processes which cause the change in resistance. They are subdivided into cation-migration cells, based on the electrochemical growth and dissolution of metallic filaments, and anion-migration cells, typically realized with transition metal oxides as the insulator, in which electronically conducting paths of sub-oxides are formed and removed by local redox processes. From this insight, we take a brief look into molecular switching systems. Finally, we discuss chip architecture and scaling issues.

http://chialvo.org/Curso/UBACurso/DIA7/Papers/Aono_NatMat_07_Ionic%20Switching%20Memory.pdf

Nanoionics-based resistive switching memories

Research Development on Sodium-Ion Batteries

Lithium-ion batteries have had a profound impact on our daily life, but inherent limitations make it difficult for Li-ion chemistries to meet the growing demands for portable electronics, electric vehicles and grid-scale energy storage. Therefore, chemistries beyond Li-ion are currently being investigated and need to be made viable for commercial applications. The use of metallic Li is one of the most favoured choices for next-generation Li batteries, especially Li-S and Li-air systems. After falling into oblivion for several decades because of safety concerns, metallic Li is now ready for a revival, thanks to the development of investigative tools and nanotechnology-based solutions. In this Review, we first summarize the current understanding on Li anodes, then highlight the recent key progress in materials design and advanced characterization techniques, and finally discuss the opportunities and possible directions for future development of Li anodes in applications.

Reviving the lithium metal anode for high-energy batteries

Recent advances in mechanics and materials provide routes to integrated circuits that can offer the electrical properties of conventional, rigid wafer-based technologies but with the ability to be stretched, compressed, twisted, bent, and deformed into arbitrary shapes. Inorganic and organic electronic materials in microstructured and nanostructured forms, intimately integrated with elastomeric substrates, offer particularly attractive characteristics, with realistic pathways to sophisticated embodiments. Here, we review these strategies and describe applications of them in systems ranging from electronic eyeball cameras to deformable light-emitting displays. We conclude with some perspectives on routes to commercialization, new device opportunities, and remaining challenges for research.

http://science.sciencemag.org/content/sci/327/5973/1603.full.pdf

Materials and mechanics for stretchable electronics

While all-solid-state batteries have built global consensus with regard to their impact in safety and energy density, their anode-less versions have attracted appreciable attention because of the possibility of further lowering the cell volume and cost. This perspective article summarizes recent research trends in anode-less all-solid-state batteries (ALASSBs) based on different types of solid electrolytes and anticipates future directions these batteries may take. We particularly aim to motivate researchers in the field to challenge remaining issues in ALASSBs by employing advanced materials and cell designs.

https://iopscience.iop.org/article/10.1088/2752-5724/acb3e8/pdf

Anode-less all-solid-state batteries: recent advances and future outlook

Regulating the morphology of lithium plating is the key to extending the cycle life of lithium metal batteries. Fatal dendritic growth is closely related to out-of-plane nucleation on the lithium metal surface. Herein, we report a nearly perfect lattice match between the lithium metal foil and lithium deposits by removing the native oxide layer using simple bromine-based acid-base chemistry. The naked lithium surface induces homo-epitaxial lithium plating with columnar morphologies and lower overpotentials. Using the naked lithium foil, the lithium-lithium symmetric cell maintains stable cycling at 10 mA cm-2 for more than 10,000 cycles, and the full-cell paired with LiFePO4 with high areal capacity of 3.3 mAh cm-2 and practical N/P ratio of 2.5 exhibits 86% capacity retention after 300 cycles. This study elucidates the usefulness of controlling the initial surface state to facilitate homo-epitaxial lithium plating for sustainable cycling of lithium metal batteries. 

/pdf/naked-metallic-skin-for-homo-epitaxial-deposition-in-lithium-2q1xnxhv.pdf

Naked metallic skin for homo-epitaxial deposition in lithium metal batteries

Rechargeable aqueous Zn metal batteries (AZMBs) are desirable because of the advantages of metallic Zn and aqueous media. However, AZMBs suffer from limited cyclability and low Coulombic efficiency, originating from uncontrolled dendrite growth and side reactions such as hydrogen gas evolution and corrosion. A hierarchically porous poly(vinylidene difluoride) (PVDF) protection layer with ferroelectric β-phases is formed on the Zn metal using a simple electrospinning method. This suppresses Zn metal failure modes such as side reactions and dendrite growth and supports rapid electrolyte accessibility. The synergetic effect of hierarchically porous structures and ferroelectricity not only facilitates a supporting matrix to form uniform nucleation sites for Zn deposition but also inhibits corrosion, allowing dendrite-free Zn deposition. This multifunctional PVDF film significantly improves the cyclability of Zn symmetric cells, allowing for up to 850 h of repeated plating/stripping cycles. Moreover, it exhibits an excellent cycle life of 1000 cycles under harsh conditions and high current densities of 4.0-10.0 mA cm-2, which are 62-fold higher than those that the bare Zn electrode tolerates.

Hierarchically Porous Ferroelectric Layer with the Aligned Dipole Moment for a High-Performance Aqueous Zn Metal Battery.

The present invention relates to a polymer-sulfur copolymer, a preparation method thereof, and a lithium-sulfur battery including the same. In the case of the polymer-sulfur copolymer according to the present invention, since the carrier is polymerized, there is no possibility that the carrier is eluted, and since the sulfur is covalently bonded to the polymer and uniformly distributed in a certain size in the copolymer, when used as a positive electrode active material for the lithium-sulfur battery, the problem of elution of the polysulfide can be improved. In addition, the polymer-sulfur copolymer according to the present invention has a high sulfur impregnation amount, thereby making it possible to realize a high capacity battery.

Polymer-sulfur copolymer, method for preparing same, and lithium-sulfur battery comprising same

Sodium ion batteries (SIBs) have many advantages such as the low price and abundance of sodium raw materials that are suitable for large-scale energy storage applications. Herein, we report an Mn-based pyrophosphate, Na(2)MnP(2)O(7), as a new SIB cathode material. Unlike most Mn-based cathode materials, which suffer severely from sluggish kinetics, Na(2)MnP(2)O(7) exhibits good electrochemical activity at ~3.8 V vs Na/Na(+) with a reversible capacity of 90 mAh g(-1) at room temperature. It also shows an excellent cycling and rate performance: 96% capacity retention after 30 cycles and 70% capacity retention at a c-rate increase from 0.05C to 1C. These electrochemical activities of the Mn-containing cathode material even at room temperature with relatively large particle sizes are remarkable considering an almost complete inactivity of the Li counterpart, Li(2)MnP(2)O(7). Using first-principles calculations, we find that the significantly enhanced kinetics of Na(2)MnP(2)O(7) is mainly due to the locally flexible accommodation of Jahn-Teller distortions aided by the corner-sharing crystal structure in triclinic Na(2)MnP(2)O(7). By contrast, in monoclinic Li(2)MnP(2)O(7), the edge-sharing geometry causes multiple bonds to be broken and formed during charging reaction with a large degree of atomic rearrangements. We expect that the similar computational strategy to analyze the atomic rearrangements can be used to predict the kinetics behavior when exploring new cathode candidates.

Jang Wook Choi

Papers

Anode-less all-solid-state batteries: recent advances and future outlook

Naked metallic skin for homo-epitaxial deposition in lithium metal batteries

Hierarchically Porous Ferroelectric Layer with the Aligned Dipole Moment for a High-Performance Aqueous Zn Metal Battery.

Polymer-sulfur copolymer, method for preparing same, and lithium-sulfur battery comprising same

Anomalous Manganese Activation of a Pyrophosphate Cathode in Sodium Ion Batteries: A Combined Experimental and Theoretical Study.