Powder metallurgical 3D nickel current collectors with plasma-induced Ni3N nanocoatings enabling long-life and dendrite-free lithium metal anode

Building three-dimensional(3D) current collectors is a promising strategy to surmount the bottlenecks of lithium metal anodes(LMAs), but the regulation methodology of a 3D current collector has seldom been considered comprehensively concerning both skeleton architectures and surface coatings. Herein, a robust porous 3D nickel skeleton(NS) with lithiophilic NiN nanocoatings(NiN@NS) is synthesized via an integrative route of powder metallurgy/plasma-enhanced nitridation technics. The facile powder metallurgical method facilitates the adjustment of NS architectures toward sufficient electrolyte adsorption and even current density distribution, while the followed plasma-enhanced chemical vapor deposition(PECVD) method can induce compact NiN nanocoatings on NS, which reduces the Li nucleation overpotential, accelerates the Li-ion transfer, and facilitates a highly reversible oriented texture of Li deposition morphology owing to the dense and homogenous deposition of Li into the pores. The optimized NiN@NS current collector shows a high averaged Coulombic efficiency(CE) of 98.8% over 350cycles, a prolonged lifespan of 1000 h(at 2 mA cm^(-2)) in symmetrical cells, together with the significant performance in full cells. The ingenious methodology reported in this work can also be broadly applicable for the controllable production of other 3D skeletons with nitride nanocoatings for various applications.

Wire-Shaped 3D-Hybrid Supercapacitors as Substitutes for Batteries

We report a wire-shaped three-dimensional(3D)-hybrid supercapacitor with high volumetric capacitance and high energy density due to an interconnected 3D-configuration of the electrode allowing for large number of electrochemical active sites,easy access of electrolyte ions,and facile charge transport for flexible wearable applications.The interconnected and compact electrode delivers a high volumetric capacitance(gravimetric capacitance)of 73 F cm−3(2446 F g−1),excellent rate capability,and cycle stability.The 3D-nickel cobalt-layered double hydroxide onto 3D-nickel wire(NiCo LDH/3D-Ni)//the 3D-manganese oxide onto 3D-nickel wire(Mn3O4/3D-Ni)hybrid supercapacitor exhibits energy density of 153.3 Wh kg−1 and power density of 8810 W kg−1.The red lightemitting diode powered by the as-prepared hybrid supercapacitor can operate for 80 min after being charged for tens of seconds and exhibit excellent electrochemical stability under various deformation conditions.The results verify that such wire-shaped 3D-hybrid supercapacitors are promising alternatives for batteries with long charge–discharge times,for smart wearable and implantable devices.

High rate and cycling stable Li metal anodes enabled with aluminum-zinc oxides modified copper foam

Metallic Li is a promising anode material for high energy density batteries but it suffers from poor stability and formation of unsafe dendrites. Previous studies demonstrated that 3 D metal foams are able to improve the stability of Li metal but the properties of these foams are inherently limited. Here we report a facile surface modification approach via magnetron sputtering of mixed oxides that effectively modulate the properties of Cu foams for supporting Li metal with remarkable stability. We discovered that hybrid Li anodes with Li metal thermally infused to aluminum-zinc oxides(AZO) coated Cu foams have significantly improved stability and reactivity compared with pristine Li foils and Li infused to unmodified Cu foams. Full cells assembled with a Li Fe PO4 cathode and a hybrid anode maintained low and stable charge-transfer resistance(<50) during 500 cycles in carbonate electrolytes, and exhibited superior rate capability(~100 m Ah g-1 at 20 C) along with better electrochemical reversibility and surface stability. The AZO modified Cu foams had superior mechanical strength and afforded the hybrid anodes with minimized volume change without the formation of dendrites during battery cycling. The rational construction of surface architecture to precisely control Li plating and stripping may have great implications for the practical applications of Li metal batteries.

Highly elastic wrinkled structures for stable and low volume-expansion lithium-metal anodes

Lithium(Li)metal is promising for high energy density batteries due to its low electrochemical redox potential and high specific capacity.However,the formation of dendrites and its tendency for large volume expansion during plating/stripping restrict the application of Li metal in practical scenarios.In this work,we developed reduced graphene oxide-graphitic carbon nitride(rGO-C3N4,GCN)with highly elastic and wrinkled structure as the current collector.Lithiophilic site C3N4 in GCN could reduce the nucleation overpotential.In addition,this material effectively inhibited electrode expansion during cycling.At the same time,due to its high elasticity,GCN could release the stress induced by Li deposition to maintain structural integrity of the electrode.Limetal anodes with GCN exhibited small volume expansion,high Coulombic efficiency(CE)of 98.6%within 300 cycles and long cycling life of more than 1700 h.This work described and demonstrated a new approach to construct flexible current collectors for stable lithium-metal anodes.

Three-dimensional lithiophilic Cu@Sn nanocones for dendrite-free lithium metal anodes

The uneven deposition of lithium(Li) on current collectors causes serious dendrite growth and volume expansion. Commercial foamed copper(Cu) current collectors are unsuitable for Li anodes because of their large volume and mass and lithiophobic nature. Herein, a three-dimensional(3 D) copper@tin(Cu@Sn) nanocone current collector with small volume, light weight, and lithiophilic nature was prepared by a simple electrodeposition method. The synergy of the nanoconical structure and lithiophilic Sn promotes the even deposition of Li and effectively inhibits the formation of Li dendrites. The resultant half batteries exhibit high Coulombic efficiency of 97.6% after 100 cycles at 1 mA cm^(-2), and the symmetrical Li battery demonstrates a prolonged lifespan of over 600 h at 1 mA cm^(-2). The full battery based on organic liquid electrolyte with LiFePO_(4) also exhibits a long lifespan of 550 cycles with high capacity retention of 95.1% at 1 C.Moreover, 3 D Cu@Sn nanocone-based solid-state batteries exhibit excellent electrochemical performance and show no decay after 500 cycles at 1 C. Our work provides a strategy for fabricating 3 D current collectors for high-energy-density Li metal batteries.