Eli Musk

A solid‐electrolyte interphase resulting from rational cathode design and optimal electrolytes enables solid‐state lithiation chemistry for Li/S and Li/Se‐S batteries, which can directly bypass the formation of highly soluble polysulfides/polyselenides, and hence significantly improve shuttle effects and long‐term cycle stability.

Abstract

Lithium/selenium‐sulfur batteries have recently received considerable attention due to their relatively high specific capacities and high electronic conductivity. Different from the traditional encapsulation strategy for suppressing the shuttle effect, an alternative approach to directly bypass polysulfide/polyselenide formation via rational solid‐electrolyte interphase (SEI) design is demonstrated. It is found that the robust SEI layer that in situ forms during charge/discharge via interplay between rational cathode design and optimal electrolytes could enable solid‐state (de)lithiation chemistry for selenium‐sulfur cathodes. Hence, Se‐doped S_22.2Se/Ketjenblack cathodes can attain a high reversible capacity with minimal shuttle effects during long‐term and high rate cycling. Moreover, the underlying solid‐state (de)lithiation mechanism, as evidenced by in situ ⁷Li NMR and in operando synchrotron X‐ray probes, further extends the optimal sulfur confinement pore size to large mesopores and even macropores that have been long considered as inferior sulfur or selenium host materials, which play a crucial role in developing high volumetric energy density batteries. It is expected that the findings in this study will ignite more efforts to tailor the compositional/structure characteristics of the SEI layers and the related ionic transport across the interface by electrode structure, electrolyte solvent, and electrolyte additive screening.

In this work, a self‐supported tin sulfide porous film is fabricated as a flexible cathode material in Al‐ion battery, which delivers a high specific capacity of 406 mAh g⁻¹. The self‐supported and flexible SnS film also shows an outstanding electrochemical performance and superior stability during dynamic and static bending tests.

Abstract

High‐performance flexible batteries are promising energy storage devices for portable and wearable electronics. Currently, the major obstacle to develop flexible batteries is the shortage of flexible electrodes with excellent electrochemical performance. Another challenge is the limited progress in the flexible batteries beyond Li‐ion because of a safety concern for the Li‐based electrochemical system. In this work, a self‐supported tin sulfide (SnS) porous film (PF) is fabricated as a flexible cathode material in an Al‐ion battery, which delivers a high specific capacity of 406 mAh g⁻¹. A capacity decay rate of 0.03% per cycle is achieved, indicating a good stability. The self‐supported and flexible SnS film also shows an outstanding electrochemical performance and stability during dynamic and static bending tests. In situ transmission electron microscopy demonstrates that the porous structure of SnS is beneficial for minimizing the volume expansion during charge/discharge. This leads to an improved structural stability and superior long‐term cyclability.

The bulk and surface defects of perovskite films are suppressed by using SnO₂/TiO₂ double layer oxide, addition of methylammonium chloride (MACl) as a crystallization aid to the precursor solution, and surface passivation of perovskite films with iodine solution, due to the formation of high‐quality large‐grain perovskite films and retardation of radiationless carrier recombination.

Abstract

The presence of bulk and surface defects in perovskite light harvesting materials limits the overall efficiency of perovskite solar cells (PSCs). The formation of such defects is suppressed by adding methylammonium chloride (MACl) as a crystallization aid to the precursor solution to realize high‐quality, large‐grain triple A‐cation perovskite films and that are combined with judicious engineering of the perovskite interface with the electron and hole selective contact materials. A planar SnO₂/TiO₂ double layer oxide is introduced to ascertain fast electron extraction and the surface of the perovskite facing the hole conductor is treated with iodine dissolved in isopropanol to passivate surface trap states resulting in a retardation of radiationless carrier recombination. A maximum solar to electric power conversion efficiency (PCE) of 21.65% and open circuit photovoltage (V _oc) of ≈1.24 V with only ≈370 mV loss in potential with respect to the band gap are achieved, by applying these modifications. Additionally, the defect healing enhances the operational stability of the devices that retain 96%, 90%, and 85% of their initial PCE values after 500 h under continuously light illumination at 20, 50, and 65 °C, respectively, demonstrating one of the most stable planar PSCs reported so far.

A stable lithium sulfur battery is enabled by a multilayer encapsulated sulfur nanocomposite electrode. The inner coating layer is a metal‐oxide capable of anchoring long‐chain polysulfides and the outer coating layer is a conductive porous polymer resulting in a battery with more than 500 cycles.

Abstract

Advancements in portable electronic devices and electric powered transportation has drawn more attention to high energy density batteries, especially lithium–sulfur batteries due to the low cost of sulfur and its high energy density. However, the lithium–sulfur battery is still quite far from commercialization mostly because of incompatibility between all major components of the battery—the cathode, anode, and electrolyte. Here a methodology is demonstrated that shows promise in significantly improving battery stability by multilayer encapsulation of sulfur particles, while using conventional electrolytes, which allows a long cycle life and an improved Coulombic efficiency battery at low electrolyte feeding. The multilayer encapsulated sulfur battery demonstrates a Coulombic efficiency as high as 98%, when a binder‐free electrode is used. It is also shown that the all‐out self‐discharge of the cell after 168 h can be reduced from 34% in the regular sulfur battery to less than 9% in the battery with the multilayer encapsulated sulfur electrode.

In article number 1801892, Steve Albrecht, Vytautas Getautis and co‐workers demonstrate a novel promising concept for the formation of a hole selective monolayer in perovskite solar cells. A low temperature dopant‐free technique makes it suitable for different substrates.

Increasing markets and decreasing package weight for high-specific-power photovoltaics

Increasing markets and decreasing package weight for high-specific-power photovoltaics, Published online: 05 November 2018; doi:10.1038/s41560-018-0258-1

Although rigid silicon panels dominate the solar power market, they are unsuitable for niche applications such as portable charging or drones, where thin-film and flexible technologies would be advantageous. This Analysis examines the needs of niche markets and the packaging weights that would be required to enable such photovoltaic devices to enter them.

Langmuir–Blodgett artificial solid-electrolyte interphases for practical lithium metal batteries

Langmuir–Blodgett artificial solid-electrolyte interphases for practical lithium metal batteries, Published online: 24 September 2018; doi:10.1038/s41560-018-0237-6

A well-designed artificial solid-electrolyte interphase (ASEI) could help resolve multiple problems associated with the use of metallic Li anodes in batteries. Here, the authors develop a Langmuir–Blodgett method to produce an ASEI composed of functionalized graphene oxide with a compatible electrolyte formulation, which facilitates a stable cycling of Li metal batteries.

Fine-tuning of the chemical structure of photoactive materials for highly efficient organic photovoltaics

Fine-tuning of the chemical structure of photoactive materials for highly efficient organic photovoltaics, Published online: 22 October 2018; doi:10.1038/s41560-018-0263-4

Materials design rules play a key role in enabling high performance in organic photovoltaics. Here the authors achieve 12.25% efficiency on 1 cm2 non-fullerene solar cells by tuning the side chains’ branching point and the fluorine substitutions in donor and acceptor materials.

Visions of energy futures

Visions of energy futures, Published online: 22 October 2018; doi:10.1038/s41560-018-0279-9

The recent German energy transition has been taken as an exemplary case for a new, decentralized and renewable-energy-based approach to energy policy worldwide. New comparative research shows, however, that its national-level interpretations outside of Germany vary considerably, reflecting country-specific contextualization and visions of a good society.

Recent advances in the growth of novel 2D materials beyond graphene and transition metal dichalcogenides are comprehensively reviewed. The in‐depth and balanced growth methods of these novel 2D materials are presented. The daunting quest for novel 2D materials poses great potential in electronics and other applications.

Abstract

Since the discovery of graphene just over a decade ago, 2D materials have been a central focus of materials research and engineering because of their unique properties and potential of revealing intriguing new phenomena. In the past few years, transition metal dichalcogenides (TMDs) have also attracted considerable attention because of the intrinsically opened bandgap. The exceptional properties and potential applications of graphene and TMDs have inspired explosive efforts to discover novel 2D materials. Here, emerging novel 2D materials are summarized and recent progress in the preparation, characterization, and application of 2D materials is highlighted. The experimental realization methods for these materials are emphasized, while the large‐area growth and controlled patterning for industrial productions are discussed. Finally, the remaining challenges and potential applications of 2D materials are outlined.

Advanced Energy Materials, Volume 8, Issue 26, September 14, 2018.

Advanced Energy Materials, Volume 8, Issue 26, September 14, 2018.

Advanced Energy Materials, Volume 8, Issue 27, September 25, 2018.

Advanced Energy Materials, Volume 8, Issue 25, September 5, 2018.

Advanced Energy Materials, Volume 8, Issue 25, September 5, 2018.

Advanced Energy Materials, Volume 8, Issue 25, September 5, 2018.

Advanced Energy Materials, Volume 8, Issue 25, September 5, 2018.

Advanced Energy Materials, Volume 8, Issue 26, September 14, 2018.

Li₂S is largely overshadowed by S as a cathode material. Some of the potential benefits of using Li₂S over S in terms of electrode packing and cycle stability are discussed. The overarching benefits may reside in the ability of Li₂S to conveniently act as the Li‐ion source for Li₂S‐based lithium‐ion batteries.

Abstract

While members of the Li–S battery research community are becoming more conscious of the practical testing parameters, the widespread commercialization of S‐based batteries is still far from realization. Particularly, the metallic Li used as the anode poses potential safety and cycle stability concerns. Alternatively, other S‐battery configurations without a Li anode, i.e., lithium‐ion, Li₂S, or S batteries, do not suffer from the same safety concerns and can possibly serve as better methods to bring room‐temperature S‐based battery technologies to industry. However, whether Li₂S or S will be used as the initiating cathode material remains unclear as each offers their own unique advantages and disadvantages. Here, both S and Li₂S as cathodes are briefly discussed and the key benefits of Li₂S are highlighted.

Advanced Materials, EarlyView.

Advanced Energy Materials, EarlyView.

Advanced Energy Materials, Volume 8, Issue 16, June 5, 2018.

Advanced Energy Materials, Volume 8, Issue 16, June 5, 2018.

Advanced Materials, EarlyView.

Advanced Materials, EarlyView.

Advanced Materials, EarlyView.

Advanced Materials, EarlyView.

Advanced Materials, EarlyView.