Regulating adsorption ability toward polysulfides in a porous carbon/Cu_(3)P hybrid for an ultrastable high-temperature lithium-sulfur battery

Lithium-sulfur batteries(LSBs)can work at high temperatures,but they suffer from poor cycle life stability due to the“shuttle effect”of polysulfides.In this study,pollen-derived porous carbon/cuprous phosphide(PC/Cu_(3)P)hybrids were rationally synthesized using a one-step carbonization method using pollen as the source material,acting as the sulfur host for LSBs.In the hybrid,polar Cu_(3)P can markedly inhibit the“shuttle effect”by regulating the adsorption ability toward polysulfides,as confirmed by theoretical calculations and experimental tests.As an example,the camellia pollen porous carbon(CPC)/Cu_(3)P/S electrode shows a high capacity of 1205.6 mAh g^(−1) at 0.1 C,an ultralow capacity decay rate of 0.038%per cycle after 1000 cycles at 1 C,and a rather high initial Coulombic efficiency of 98.5%.The CPC/Cu_(3)P LSBs can work well at high temperatures,having a high capacity of 545.9 mAh g^(−1) at 1 C even at 150℃.The strategy of the PC/Cu_(3)P hybrid proposed in this study is expected to be an ideal cathode for ultrastable high-temperature LSBs.We believe that this strategy is universal and worthy of in-depth development for the next generation energy storage devices.

Carbonized waste milk powders as cathodes for stable lithium-sulfur batteries with ultra-large capacity and high initial coulombic efficiency

To explore the natural resources as sustainable precursors offers a family of green materials.The use of bio-waste precursors especially the remaining from food processing is a scalable,highly abundant,and cost-effective strategy.Exploring waste materials is highly important especially for new materials discovery in emerging energy storage technologies such as lithium sulfur batteries(LSBs).Herein,waste milk powder is carbonized and constructed as the sulfur host with the hollow micro-/mesoporous framework,and the resulting carbonized milk powder and sulfur(CMP/S) composites are employed as cathodes for LSBs.It is revealed that the hollow micro-/mesoporous CMP/S framework can not only accommodate the volume expansion but also endow smooth pathways for the fast diffusion of electrons and Li-ions,leading to both high capacity and long cycling stability.The CMP/S composite electrode with 56 wt% loaded sulfur exhibits a remarkable initial capacity of 1596 mAh g^(-1) at 0.1 C,corresponding to 95% of the theoretical capacity.Even at a rate of 1 C,it maintains a high capacity of 730 mAh g^(-1) with a capacity retention of 72.6% after 500 cycles,demonstrating a very low capacity fading of only 0.05% per cycle.Importantly,the Coulombic efficiency is always higher than 96%during all the cycles.The only used source material is expired waste milk powders in our proposal.We believe that this "trash to treasure" approach will open up a new way for the utilization of waste material as environmentally safe and high performance electrodes for advanced LSBs.

Flexible and biocompatible nanopaper-based electrode arrays for neural activity recording

Advances in neural electrode technologies can have a significant impact on both fundamental and applied neuroscience. Here, we report the development of flexible and biocompatible neural electrode arrays based on a nanopaper substrate. Nanopaper has important advantages with respect to polymers such as hydrophilicity and water wettability, which result in significantly enhanced biocompatibility, as confirmed by both in vitro viability assays and in vivo histological analysis. In addition, nanopaper exhibits high flexibility and good shape stability. Hence, nanopaper-based neural electrode arrays can conform to the convoluted cortical surface of a rat brain and allow stable multisite recording of epileptiform activity in vivo. Our results show that nanopaper-based electrode arrays represent promising candidates for the flexible and biocompatible recording of the neural activity.

Design of hierarchical and mesoporous FeF_(3)/rGO hybrids as cathodes for superior lithium-ion batteries

Iron fluoride(FeF_(3)) is considered as a promising cathode material for Li-ion batteries(LIBs)due to its high theoretical capacity(712 mAh/g)with a 3 e-transfer.Herein,we have designed a strategy of hierarchical and mesoporous FeF_(3)/rG O hybrids for LIBs,where the hollow Fe F_(3) nanospheres are the main contributor to the specific capacity and the 2 D r GO nanosheets are the matrix elevating the electronic conductivity and buffering the volume expansion.The unique FeF_(3)/rGO hybrid can be rationally synthesized by a nonaqueous in-situ precipitation method,offering the merits of large specific surface area with rich active sites,fast transport channels for lithium ions,effective alleviation of volume expansion during cycles,and accelerating the electrochemical reaction kinetics.The Fe F_(3)/r GO hybrid electrode possesses a high initial discharge capacity of 553.9 m Ah/g at a rate of 0.5 C with 378 m Ah/g after 100 cycles,acceptable rate capability with 168 m Ah/g at 2 C,and feasible high-temperature operation(320 m Ah/g at 70℃).The superior electrochemical behaviors presented here demonstrates that the FeF_(3)/rGO hybrid is a potential electrode for LIBs,which may open up a new vision to design high-efficiency energy-storage devices such as LIBs based on transition metal fluorides.