Air-stable organic crystal-based metal-ion batteries (MIBs) working in conventional electrolyte concentrations are important for cost-effective renewable energy storage. In the dearth of such stable "organic metal reservoirs," a family of porphyrin-fused extended conjugated sulfonamide compounds (ECSA) has been demonstrated for MIBs of lithium-ion batteries (LIBs). ECSA forms a class of metalloporphyrins (M(4)ZnSOTAPP) having different metal ion possibilities (M = Li+/Na+/K+) with four redox meso-positions. The discharge voltage of Li(4)ZnSOTAPP crystal-based LIB is found to be 2.5 V versus Li/Li+, in line with the theoretical calculations having a theoretical capacity of similar to 100 mAh g(-1) for a cell constructed in practically relevant conditions having 1 M electrolyte. Further to the demonstration of stable performance of Li(4)ZnSOTAPP in LIB (similar to 77% capacity retention at 1000 cycles), its optical activity, crystal structure, and the charge-discharge mechanism have been unraveled. Combined experimental and computational analyses suggest that the sulfonamide groups serve as the primary redox-active centers for lithium-ion storage, while the extended porphyrin-fused conjugated framework facilitates charge delocalization during cycling. Demonstration of K(4)ZnSOTAPP crystals further establishes the avenue for pi-extended structures based beyond Li organic batteries.

Developing largely available carbon-based, extremely stable electrode materials for next-generation metal ion batteries is a need of the hour. Here, a facile route to Fe and N-modified mesoporous carbon structures from polypyrrole and melamine is demonstrated for reversible sodium ion insertion and de-insertion (for >10000 cycles) in a sodium ion battery backdrop. The derived carbon-based anode material has a 'sheet on sphere' morphology, with a capacity of similar to 380 mAh g(-1) for more than 4000 cycles and a high current density of 2.5 A g(-1). Extended cycling to >10000 also delivers a high capacity of 300 mAh g(-1) at 2.5 A g(-1), indicating its potential as a high shelf-life anode for extreme cyclability sodium-ion batteries. Possibilities of further enhancement in the sodium ion storage capacity (similar to 600 mAh g(-1)) by tuning the charge-discharge voltage window (3.3 V- 0.01 V vs Na/Na+) are demonstrated, leading to the demonstration of the highest capacity material, indicating the potential structural tunability of the composite matrix for high-capacity sodium-ion batteries.

Does light or heat play a seminal role in photo-rechargeable batteries? This study unravels the effects of light in the exciton formation and separation processes in a photocathode, leading to the charging or de-intercalation of Li+ ions in a lithium-ion battery. Light induced oxidation of Ti3+ to Ti4+ in the Lix(TiS2-TiO2) heterostructure cathode is shown here, while heating does not elicit such changes. With the aid of photogenerated electrons at the cathode, the de-lithiated Li+ ions from Lix(TiS2-TiO2) get intercalated in the graphite anode during the photocharging process. Direct or passive heating leads to the degradation of the cathode electrolyte interface (CEI), instigating enhancement in open circuit potential. In contrast, photocharging leaves the organic electrolytes and CEI unaffected. Hence energy efficient photo-electrochemical energy systems can be built by carefully isolating the effects of heat and light in solar radiation, as dictated by this study.

Layered semiconductor materials such as transition metal dichalcogenides are known to undergo phase transition from the semiconducting (H) to a metallic/quasi-metallic ( T/T^' ) phase upon ion intercalation, thus changing their physical and electronic properties. Initially, based on a computational set-up that treats both phases (H and T’) on the same footing and allows extraction of electron density from lithium intercalated MoS2, we predict that the phase transition can be delayed in MoS2 with almost 1.5 times the amount of cation accommodation while the layers are in contact with another material (MoO3), forming a type-II heterostructure. This important theoretical prediction is then validated via in situ Raman spectroscopy and electron transport measurements, where the concentration of the intercalated Li-ions is controlled by applying an external voltage. The ability to store more Li-ions in the same phase extends the scope of these heterostructures in light driven processes/devices, e.g. photocatalysis, and light-chargeable batteries.

Chemical stability of hexagonal boron nitride (hBN) ultra-thin layers in harsh electrolytes and the availability of nitrogen site to stabilize metals like Pt are used here to develop a high intrinsic activity hydrogen evolution reaction (HER) catalyst having low loaded Pt (5 weight% or < 1 atomic%). A catalyst having non-zero oxidation state for Pt (with a Pt-N bonding) is shown to be HER active even with low catalyst loadings (0.114 mgcm-2). Electronic modification of the shear exfoliated hBN sheets is achieved by Au nanoparticle-based surface decoration (hBN_Au), and further anchoring with Pt develops a catalyst (hBN_Au_Pt) with high turnover frequency for HER (~15), which is ~1.8 times higher than the benchmarked Pt/C HER catalyst. The hBN_Au_Pt is shown to be a highly durable catalyst even after the accelerated durability test for 10000 cycles and temperature annealing of 100 oC. Density functional theory-based calculations gave insights in to the electronic modifications of hBN with Au and the catalytic activity of the hBN_Au_Pt system, in line with the experimental studies, indicating the demonstration of a new class of catalyst system devoid of issues such as carbon corrosion and Pt leaching.

: In recent times photorechargeable metal ion batteries have garnered significant attention but the atomistic details of the mechanism of the charging process is still unknown. MoS 2 /MoO y , a type II semiconductor heterostructure, has been shown to function as photocathode where during discharge the lithium ion (Li-ion) intercalation happens mostly in MoS 2 layers. Photo-exposure leads to exciton formation and the type II set-up is supposed to generate spatially separated and longer-lived charge carriers. The Li intercalated MoS 2 is known to undergo a phase transition from the semiconducting (2H) to a metallic (1T’) phase. Hence, the proposal of exciton formation and its separation in Li x MoS 2 during photocharging needs closer inspection. In this study, with the help of density functional theory (DFT) based studies that is aptly supported by experimental data, it is shown that Li x MoS 2 /MoO 3 forms a type II heterostructure where the underlying band gap of Li x MoS 2 is exposed due to dispersion of electron density onto MoO 3 upto a certain value of x. Further studies show that the type II arrangement is lost prior to the phase transition. In order to investigate the electronic structure and the phase transition upon lithiation in the explicit heterostructure, we introduced two unconventional computational schemes. The presence of the band gap and the ensuing type II arrangement in Li x MoS 2 /MoO 3 upto a certain concentration of the intercalated Li-ion justifies the possibility of the photocharging process. We believe that the general concepts explored in this study will be important in the rational design of type II heterostructures that can behave as photo-cathode materials in Li-ion batteries.

Light chargeable metal-ion batteries using semiconductor heterostructures are gaining enormous interest. A few such heterostructures such as MoS2/MoOy and TiS2/TiO2 have been shown to function as photocathodes in photochargeable Li-ion batteries, where the type II set-up has been proposed to generate spatially separated (longer-lived) excitons upon photo-exposure. The Li intercalated MoS2, generated during the discharge cycle of the battery, undergoes a phase transition from the semiconducting (2H) to a metallic (1T) phase, in contrast to its TiS2 counterpart, casting a doubt over the photocharging process. Here, employing density functional theory based traditional as well as unconventional computational schemes along with relevant spectroscopic techniques, we show that in LixMoS2/MoO3 heterostructure an underlying band gap of LixMoS2 is exposed, upto a certain value of x, due to dispersion of electron density onto MoO3 justifying the observed photocharging. We believe that the general concepts explored in this study will be important in the rational design of photo-cathode materials in Li-ion batteries.

The investigation on the designing and fabrication of highly efficient electrocatalysts for hydrogen evolution reaction (HER) is critical for future applications in renewable sustainable energy. The present work reports the hydrothermal synthesis of two-dimensional MoS 2 and MoS 2 -TiO 2 nanostructures. The as-prepared nanostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman analysis, UV–vis-NIR, and photoluminescence spectrophotometry and vibrating sample magnetometer (VSM). Systematic electrochemical measurements for HER were performed and MoS 2 -TiO 2 nanocomposites demonstrated the lowest onset potential in comparison with MoS 2 . The results suggest that the nanofusion interface between MoS 2 nanoflakes and TiO 2 nanoparticles induced an efficient charge transfer from the conduction band of MoS 2 to TiO 2 and favored the reduction of H + at active sites. We believe the present work can open up new possibilities that would provide deep insights for the rational design of 2D materials-based catalysts for energy storage and conversion applications.

Photo-rechargeable (solar) battery can be considered as an energy harvesting cum storage system, where it can charge the conventional metal-ion battery using light instead of electricity, without having other parasitic reactions. Here a two-electrode lithium-ion solar battery with multifaceted TiS2 -TiO2 hybrid sheets as cathode. The choice of TiS2 -TiO2 electrode ensures the formation of a type II semiconductor heterostructure while the lateral heterostructure geometry ensures high mass/charge transfer and light interactions with the electrode. TiS2 has a higher lithium binding energy (1.6 eV) than TiO2 (1.03 eV), ensuring the possibilities of higher amount of Li-ion insertion to TiS2 and hence the maximum recovery with the photocharging, as further confirmed by the experiments. Apart from the demonstration of solar solid-state batteries, the charging of lithium-ion full cell with light indicates the formation of lithium intercalated graphite compounds, ensuring the charging of the battery without any other parasitic reactions at the electrolyte or electrode-electrolyte interfaces. Possible mechanisms proposed here for the charging and discharging processes of solar batteries, based on the experimental and theoretical results, indicate the potential of such systems in the forthcoming era of renewable energies.

Tin antimony alloy anchored reduced graphene oxide (rGO-SnxSby (x similar to y = 1)) composite, prepared in bulk via a facile chemical route, is shown for its applicability in high current density (500 mAg(-1)) charging/discharging sodium battery application. The composite electrode delivered similar to 320 mAhg (1) capacity in>300 cycles with Sodium as the other electrode. This electrode material retains similar to 300 mAhg(-1) specific capacity at a 500 mAg(-1) specific current density even after 2.5 Ag(-1)charge-discharge rates, indicating its potential in fast charge-discharge energy storage applications. The systematic study conducted here indicates that synergistic effects from the alloy particles and the rGO conductive matrix are leading to this observed phenomenon. The development of such viable anode materials can play a pivotal role in the commercialisation of sodium ion secondary batteries, one of the potential systems for future energy storage applications.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Herein we report secondary pyrrolidin-2-ols as a source of cyclic (alkyl)(amino)carbenes (CAAC) for the synthesis of CAAC-Cu-I-complexes and cyclic thiones when reacted with Cu-I-salts and elemental sulfur, respectively, under reductive elimination of water from the carbon(IV)-center. This result demonstrates a convenient and facile access to CAAC-based Cu-I-salts, which are well known catalysts for different organic transformations. It further establishes secondary alcohols to be a viable source of carbenes-realizing after 185 years Dumas' dream who tried to prepare the parent carbene (CH2) by 1,1-dehydration of methanol. Addressed is also the reactivity of water towards CAACs, which proceeds through an oxidative addition of the O-H bond to the carbon(II)-center. This emphasizes the ability of carbon-compounds to mimic the reactivity of transition-metal complexes: reversible oxidative addition and reductive elimination of the O-H bond to/from the C(II)/C(IV)-centre.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

New ways of directly using solar energy to charge electrochemical energy storage devices such as batteries would lead to exciting developments in energy technologies. Here, a two-electrode photo-rechargeable Li-ion battery is demonstrated using nanorod of type II semiconductor heterostructures with in-plane domains of crystalline MoS2 and amorphous MoOx. The staggered energy band alignment of MoS2 and MoOx limits the electron holes recombination and cause holes to be retained in the Li intercalated MoS2 electrode. The holes generated in the MoS2 pushes the intercalated Li+ ions and hence, charge the cell. Low band gap, high efficiency photo-conversion and efficient electron-hole separation help the battery to fully charge within a few hours with a low power light. The proposed concept and materials could enable next generation stable solar chargeable battery electrodes, in contrast to the reported materials.