Wenhua YuYanyan WangAimin WuAikui Li...
138-151页查看更多>>摘要：Improving the reversibility of anionic redox and inhibiting irreversible oxygen evolution are the main challenges in the application of high reversible capacity Li-rich Mn-based cathode materials.A facile synchronous lithiation strategy combining the advantages of yttrium doping and LiYO2 surface coating is proposed.Yttrium doping effectively suppresses the oxygen evolution during the delithiation process by increasing the energy barrier of oxygen evolution reaction through strong Y-O bond energy.LiYO2 nanocoating has the function of structural constraint and protection,that protecting the lattice oxygen exposed to the surface,thus avoiding irreversible oxidation.As an Li+conductor,LiYO2 nano-coating can provide a fast Li+transfer channel,which enables the sample to have excellent rate performance.The synergistic effect of Y doping and nano-LiYO2 coating integration suppresses the oxygen release from the surface,accelerates the diffusion of Li+from electrolyte to electrode and decreases the interfacial side reactions,enabling the lithium ion batteries to obtain good electrochemical performance.The lithium-ion full cell employing the Y-1 sample(cathode)and commercial graphite(anode)exhibit an excellent specific energy density of 442.9 Wh kg-1 at a current density of 0.1C,with very stable safety performance,which can be used in a wide temperature range(60 to-15 ℃)stable operation.This result illustrates a new integration strategy for advanced cathode materials to achieve high specific energy density.
Jingwen MaXiang LiGuangyu LeiJun Wang...
152-162页查看更多>>摘要：The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems,but it is still a challenge.NMPs have attracted increasing attentions,but the preparation process often needs toxic regents or dangerous reaction conditions.Herein,we develop a general green method to fabricate metal-rich NMPs anchored on NPG through pyrolyzing DNA cross-linked complexes.The obtained Ru2P-NPG exhibits an ultrasmall overpotential of 7 mV at 10 mA cm-2 and ultralow Tafel slope of 33 mV dec-1 in 1.0 mol L-1 KOH,even better than that of commercial Pt/C.In addition,Ru2P-NPG also shows low overpotentials of 29 and 78 mV in 0.5 mol L-1 H2SO4 and 1.0 mol L-1 PBS,respectively.The superior activity can be attributed to the ultrafine dispersion of Ru2P nanoparticles for more accessible sites,more defects formed for abundant active sites,the two-dimensional plane structure for accelerated electron transfer and mass transport,as well as the regulation of electron distribution of the catalyst.Moreover,the synthetic method can also be applied to prepare other metal-rich noble metal phosphides(Pd3P-NPG and Rh2P-NPG),which also exhibits high activity for HER.This work provides an effective strategy for designing NMP-based electrocatalysts.
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