The Preparation And Electrochemical Performance Of High-performance Alkali Metal Ion Battery Anode Materials

In recent years,the development strategy of new energy has risen to the national level,the alkaline metal ion?Li⁺/Na⁺/K⁺?batteries have attracted more and more attention from enterprises and researchers because of their abundant advantages.Currently,the specific capacity(372 mAh g^-1)of commercial graphite anode is too low to satisfy the demand of market.Graphene is considered as one of the most promising anode materials for alkali ion batteries in term of large specific surface area and high conductivity,whereas,low initial Coulombic efficiency,poor capacity and fast capacity decay severely block the commercialization process.Transition metal oxides benefit from their higher theoretical capacity,unfortunately,they are prone to pulverization and agglomeration during charge/discharge,which will lead to poor cycling performance and rate ability.Some strategies including regulating morphology,substitutional doping,and carbon-coating,have been proposed to address the above drawbacks.Herein,this paper describes the anode materials of alkaline metal ion batteries as well as their reaction mechanisms.Furthermore,some detailed analyses were discussed on the structure and composition of the above materials,and the electrochemical performance as anodes were tested.The comparative experiments confirmed that the materials prepared are superior in electrochemical performances.The main contents of this article are as follows:?1?The reduced graphene oxide with three-dimensional interconnected hollow channel structure?3D IH-rGO?was synthesized via electrospinning/electrospray and carbonization methods.The stable 3D interconnected hollow channel architecture can efficiently alleviate the pulverization and agglomeration of electrode.In addition,this unique structure can offer more transmission pathways and absorption sites,which greatly improve the alkali ion storage ability during charge/discharge.3D IH-rGO electrode exhibits extraordinary lithium,sodium and potassium storage performance.For LIBs,3D IH-rGO possesses high initial Coulombic efficiency?74.0%?and superior initial storage capacity(1167.0 mAh g^-1)at 0.5 A g^-1.For NIBs and KIBs,3D IH-rGO still endows good reversible capacity of 249.5 mAh g^-1 and 215.7 mAh g^-1 at 0.2 A g^-1over 100 cycles,respectively.?2?Litchi-like MnCo₂S₄@C was prepared by hydrothermal method.The synergistic effect of Mn and Co metals and carbon coating further alleviated the volume expansion of MnCo₂S₄,and more redox reactions can increasing capacity during cycling process.At a current density of 0.2 A g^-1,the charge specific capacity of the MnCo₂S₄@C electrode is as high as 1648.8 mAh g^-1 after 100 cycles.The specific capacity of the MnCo₂S₄@C can reach 1961.8 m Ah g^-1 at 3 A g^-1 over 500 cycles.?3?The MnO@NCC was prepared by the hydrothermal method with the assistance of aniline and glucose.This structure alleviates the volume expansion of MnO during charge/discharge,and N-doping also improves the conductivity of MnO.MnO@NCC exhabits high specific capacity and excellent cycle performance in lithium-ion battery.MnO@NCC delivers the specific capacity of 2907.2 mAh g^-11 over 250 cycles at 0.2 A g^-1.After 1000 cycles at 5 A g^-1,MnO@NCC shows the specific capacity of 730.3 mAh g^-1,and the capacity retention rate keeps 99.5%.