In situ formed three-dimensional (3D) lithium-boron(Li-B) alloy as a potential anode for next-generation lithium batteries

The practical application of the lithium anode in lithium metal batteries(LMBs) has been hindered by the uncontrollable growth of lithium dendrite and the high volumetric change during cycling. Herein, the in situ formed three-dimensional(3D) lithium-boron(Li-B) alloy is suggested as an excellent alternative to the Li metal, in which the 3D Li B skeleton can mitigate the growth of Li dendrites and volumetric change. In this study, the Li-B alloy anodes with different B contents were manufactured by high-temperature melting. It was found that the boron content had a significant effect on the electrochemical performance of the Li-B alloy. The Li-B alloy with the least B content(10 wt%, 10LiB) demonstrated the lowest overpotential of 0.0852 V after 300 h and the lowest interface resistance. However, the full cell with 15LiB as the anode displayed the best cycling performance of 115 m Ah·g^(-1) after 100 cycles with a columbic efficiency greater than 97%. The obtained results suggest that the in situ formed three-dimensional Li-B alloy anode can be an excellent alternative to the Li anode via tuning B contents for next-generation high energy density LMBs.

NiCoO2/NiCoP@Ni nanowire arrays:tunable composition and unique structure design for high-performance winding asymmetric hybrid supercapacitors

Transition metal phosphides(TMPs)are recognized as such promising supercapacitor materials for the practical application,due to their superior electrical conductivity and excellent redox activity.Here,self-supported three-dimensional NiCoP nanoparticles embedded in NiCoO2 nano wires(NiCoO2/NiCoP)electrode consisting of nickel cobalt phosphides(NiCoP)with high activity and nickel cobalt oxides(NiCoO2)with good stability were fabricated by a hydrothermal and phosphorization method.The electrode integrates the advantages of nanowire arrays for fast ion transport and foam Ni for effective charge transport and flexibility.Benefitting the proper composition control of the nanohybrid and unique structure design,the optimized NiCoO2/NiCoP-20 exhibits a high specific capacitance of 3204 F·g-1 at 1 A·g-1 in 3 mol·L-1 KOH aqueous electrolyte in a three-electrode system.Moreover,the asymmetric supercapacitor assembled with the prepared NiCoO2/NiCoP-20 and activated carbon achieves a specific capacitance of 116 F·g-1 with a high energy density of 40.32 Wh·kg-1 at the power density of 800.18 W·kg-1.The practical application is further demonstrated with all-solid-state winding supercapacitor devices,with decent flexibility,in series to light the Central South University(CSU)logo consisting of 21 red LED indicators.

A nanostructured Ni/T-Nb_(2)O_(5)@carbon nanofibers as a long-life anode material for lithium-ion batteries

In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treatment.The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency.Ni/T-Nb_(2)O_(5)nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system,which provides effective buffering during the lithiation/delithiation process for cycling stability.The Ni/TNb_(2)O_(5)@CNFs show high surface area(26.321 m^(2)·g^(-1))and mesoporous microstructure,resulting in higher capacity and excellent rate performance.The Ni/T-Nb_(2)O_(5)@CNFs exhibit a remarkable capacity of 437 mAh·g^(-1)at a current density of0.5 A·g^(-1)after 230 cycles and a capacity of 173 mAh·g^(-1)at a current density up to 10.0 A·g^(-1)after 1400 cycles.This work indicates that nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs.

Coating highly lithiophilic Zn on Cu foil for high-performance lithium metal batteries

Lithium metal batteries(LMBs) are ideal candidates for next-generation high energy density energy storage systems.However,uncontrollable growth of Li dendrites due to uneven Li plating has restricted the practical application of the Li metal anode.Here,we develop a highly lithiophilic Zn coating on commercial Cu foil as a substrate for Li metal anode to settle above issues.We find that the lithiophilic nature of Zn can facilitate homogeneous nucleation and deposition of Li on Cu current collector surface.In addition,the uniform Zn coating can not only decrease the nucleation overpotential but also regulate the electric field distribution.Benefiting from the coated Zn layer,the designed anode for half-cell and full-cell tests shows better electrochemical performances compared with the untreated Cu foil.This work provides a simple and effective way to enable a promising dendrite-free lithium metal anode for large-scale industrial applications.