Alternating nanolayers as lithiophilic scaffolds for Li-metal anode

Nanostructured scaffolds offer promising opportunities in enabling dendrite-free long-cycle life Li metal anode.The rational design and controllable synthesis of scaffolding architectures are imperative for development of rechargeable Li metal batteries.In this study,we explore the fabrication and application of a tin monoxide/graphene hybrid architecture as a lithiophilic host for high-performance Li metal anode.Using a polymer-assisted sonochemical synthesis route,we tuned the thickness of SnO nanolayers and the nanostructure of alternatively stacking thin SnO nanosheet/graphene(SnO-NS/G) heterostructure.Offering abundant nucleation sites,fast ion transport tunnels,and 3D-conductivity,the unique 2D-2D architecture enables stable lithium plating-stripping cycling with low nucleation overpotential and high coulombic efficiency(CE).Hosted by SnO-NS/G scaffold,the resulting Li metal anode exhibits stable cycling over 200 cycles at 0.5 mA cm^(-2)(2 mAh).Full cell pairing high-mass-loading cathode LiCoO_(2)(LCO)(12 mg cm^(-2)) with SnO-NS/G hosted Li metal anode delivers high energy density of 402 Wh kg^(-1) and stable cyclability of over 100 cycles.We elucidate the structure-property relationship between nanolayer thickness and Li-metal plating behaviors,giving new insight on structuring 2D-nanomaterials with ideal architectures for stable lithium metal batteries.

Size and near-surface engineering in weak-oxidative confined space to fabricate 4 nm L1_(0)-PtCo@Pt nanoparticles for oxygen reduction reaction

The near-surface structure of the Pt-based alloy including the surface and subsurface structures is prominent to their electrocatalytic performance.Modulating the near-surface structure of PtCo intermetallics with small particle size could efficiently optimize the binding force between Pt and oxygen and finally enhance its oxygen reduction reaction(ORR)performance.Here we simultaneously achieve the size controlling and surface modulation of intermetallic nanoparticles(NPs)in a weak-oxidative confined space with abundant uncoordinated oxygen atoms.1–2 atomic layers of concave Pt-rich surface were successfully constructed on 4 nm L1_(0)-PtCo core after removing Co–O species which is derived from the segregation of the subsurface Co to the surface induced by the uncoordinated oxygen atoms.Owing to the elaborate structure,PtCo-1000/C catalyst shows significant improvement in both activity(1.290 A∙mg_(Pt)^(−1)and 1.529 mA∙cm_(Pt)^(−2) at 0.9 V vs.reversible hydrogen electrode(RHE))and stability(85.2%of initial mass activity after accelerated degression tests(ADTs))even the production is scaled up to gram level.Density functional theory calculations suggest that the cave Pt site optimizes the protonation of*O,which finally boosts the ORR performance.

基于铝离子与–NH基团相互作用的高性能铝-聚苯胺电池

铝离子电池作为一种高容量、高电荷转移率、低成本和高安全性的储能器件具有良好的应用前景.但是,阴极材料的电化学性能限制了铝离子电池的进一步发展,例如目前研究最多的石墨类电极材料容量较低,而过渡金属氧族化合物电极材料的循环稳定性相对较差.本论文根据第一性原理的计算结果,开发出一种聚苯胺/氧化石墨烯复合材料,该复合材料作为铝离子电池阴极材料表现出极为出色的电化学性能(4000次循环后比容量依然能维持180 mA hg^-1).多种非原位表征实验证明,在充电过程中聚苯胺通过其–NH基团与电解质阴离子(如AlCl4^-)之间的适度相互作用进行电荷存储.本研究为基于导电聚合物正极材料的高性能铝离子电池的发展奠定了基础.