Microzone-explosion synthesis of porous carbon electrodes for advanced aqueous solid-state supercapacitors with a high-voltage gel electrolyte

A new microzone-combustion synthesis is proposed for preparing S, N-doped hierarchically porous carbons(CAC-CN) with a novel mixed microstructure of sp~2 short-range order area and sp~3 defective area,achieving a coexistence of high conductivity and high capacitance as well as good access for electrolyte.By engineering ‘‘water in salts" into a polymer matrix, a high-voltage(2.5 V) aqueous gel electrolyte(HGWIS) is prepared and used to construct an aqueous solid-state SCs by in situ polymerization between the electrodes. The good match of CAC-CN electrode and HG-WIS electrolyte endows the assembled devices with superior high energy density and excellent capacitance retention, also a good temperature robustness, as well a high flexibility in 0-180° bending cycles. This study indicates that the collaborative design strategy of electrode materials and electrolyte would be great potential in exploring advanced aqueous solid-state SCs.

Amorphous Se species anchored into enclosed carbon skeleton bridged by chemical bonding toward advanced K-Se batteries

Potassium-selenium(K-Se)batteries have attracted significant attention as one of the most promising alternatives of lithium-ion storage systems owing to high energy density and low cost.In the design of Se-based cathode materials,however,the low utilization rate of active Se and the rapid dissolution of polyselenides seriously weaken the capacity and cycle stability.Therefore,how to make full use of Se species without loss during the charge and discharge process is the key to design high-performance Se-based cathode.In this paper,a 3 D"water cube"-like Se/C hybrid(denoted as Se-O-PCS)is constructed with the assistance of Na_(2)CO_(3) templates.Thanks to the abundant carbonate groups(CO_(3)^(2-))originated from the Na_(2)CO_(3) templates,the molten Se species are firmly anchored into the pore of carbon skeleton by strong C-O-Se bonding.Thus,this unique Se-O-PCS model not only improves the utilization of active Se species,but also can reduce the contact with the electrolyte to inhibit the shuttle effect of polyselenides.Moreover,flexible carbon skeleton gives Se-O-PCS hybrid a good electrical conductivity and excellent structural robustness.Consequently,the resultant Se-O-PCS hybrid is endowed with an obviously enhanced K-ions storage property.

Soil salinization increases the stability of fungal not bacterial communities in the Taklamakan desert

●Bacterial richness declined but fungal richness increased under salinization.●Bacteria did not become interactively compact or facilitative under salinization.●Fungi exhibited more compartmentalized and competitive patterns under salinization.●Fungal stability showed steeper increases under salinization than bacterial stability.Soil salinization is a typical environmental challenge in arid regions worldwide.Salinity stress increases plant convergent adaptations and facilitative interactions and thus destabilizes communities.Soil bacteria and fungi have smaller body mass than plants and are often efficient against soil salinization,but how the stability of bacterial and fungal communities change with a wide range of soil salinity gradient remains unclear.Here,we assessed the interactions within both bacterial and fungal communities along a soil salinity gradient in the Taklamakan desert to examine(i)whether the stability of bacterial and fungal communities decreased with soil salinity,and(ii)the stability of which community decreased more with soil salinity,bacteria or fungi.Our results showed that the species richness of soil fungi increased but that of soil bacteria decreased with increasing salinity in topsoils.Fungal communities became more stable under soil salinization,with increasing compartmentalization(i.e.,modularity)and proportion of competitions(i.e.,negative:positive cohesion)as salinity increased.Bacterial communities exhibited no changes in modularity with increasing salinity and smaller increases in negative:positive cohesion under soil salinization compared to fungal communities.Our results suggest that,by altering interspecific interactions,soil salinization increases the stability of fungal not bacterial communities in extreme environments.

Construction of Frame-Structured Flexible MXene Film Electrode to Achieve High Areal Capacitance Micro-Supercapacitor

Two-dimensional MXene-based film materials as flexible electrodes have been widely studied in wearable microsupercapacitors(MSCs).However,the existence of strong van derWaals interactions leads to serious self-stacking ofMXene layers,resulting in poor ionic dynamics and loss of active sites,which causes MXene film electrodes to exhibit low capacitance and poor rate performance in practical studies.To solve this,a frame-structured hybrid film(labeled as CN-MX hybrid film)is constructed by introducing intercalating agents(nanometer g-C_(3)N_(4))into MXene layers.In this unique hybrid film,the g-C_(3)N_(4)nanoparticles rationally occupy the interspace between MXene layers so as to alleviate layer stacking,thus effectively expanding the electrochemically active surface and promoting proton transfer.Synergistic pseudocapacitance inducted by g-C_(3)N_(4)surface groups,consequently,the CN-MX hybrid film electrode achieves an enhanced capacitive capability.In the three-electrode system,this frame-structured film electrode exhibits an ultra-high areal capacitance of 1932.8 mF cm^(−2).The assembled symmetry flexible MSC device based on CN-MX hybrid film can achieve an energy density of 2.28μWh cm^(−2)at 0.075 mW cm^(−2),as well as a superior cyclic stability with 90.4%retention after 700 cycles in alternating 90o bending and releasing states,revealing its potential in practical applications.

Soil organic carbon saturation deficit under primary agricultural managements across major croplands in China

Introduction:To generate information for the effective management of soil organic carbon(SOC)sequestration in Chinese croplands,we compared the additional organic carbon(C)that can be stabilized by fine soil particles(<20μm)with typical fertilization practices across soil types and climate zones.Using data from 30 long-term experimental study sites across the major agricultural zones in China,we estimated stable SOC saturation deficit(SOC_(deficit))under no fertilization(CK),chemical fertilization(CF),straw plus CF(S+CF),and manure plus CF(M+CF).Stable SOC_(deficit)was defined as the difference between potential and current SOC stabilized by fine soil particles.Outcomes:Stable SOC_(deficit)values varied from 51%to 82%.Soils dominated by 2:1 clay minerals showed larger stable SOC_(deficit)than soils dominated by 1:1 clay minerals under each treatment.For soils dominated by 2:1 clay minerals,stable SOC_(deficit)was significantly lower under M+CF(69%)than under CK,CF,and S+CF(78-82%)treatments,and it increased with increasing mean annual temperature(<10°C).In soils dominated by 1:1 clay minerals,stable SOC_(deficit)was considerably lower in paddy and paddy-upland than in upland soils,suggesting that paddies effectively stabilize C inputs.Discussion:Agricultural soils in China have considerable C sequestration potential,despite decades of fertilization practices.To manage soil C sequestration and model soil C dynamics effectively,factors such as soil mineral types,fertilization,and cropland use should be considered.Conclusion:Our results demonstrated that manure addition was the best fertilization method for improving soil fertility,whereas straw return in Chinese croplands should take into account climate mitigation in future.