Modification And Application Of Tin Dioxide Based Anodes For Lithium/Potassium Ion Batteries

Lithium-ion battery?LIB?has been considered as one of the most promising energy storage systems.However,accompanied by the development of electric vehicles,traditional graphite anodes cannot fit the demand of industrial application due to their low theoretical reversible capacity(372 m Ah g^-1).Thus,it is highly desirable to explore novel anode materials with high capacity,good rate performance and excellent cycling stability for the next-generation lithium-ion batteries.Particularly,tin dioxide is an important candidate for alloy-based anodes due to its low cost and high theoretical specific capacity.Nevertheless,the low intrinsic conductivity,huge volume expansion lead to poor rate performance and rapidly capacity fading.To solve the problems of Sn O₂ in LIBs,we have successfully synthesized polyacrylamide/Sn O₂ nanocrystals/graphene gel composite anode by thermochemical reduction and in-situ polymerization,in which Sn O₂ nanocrystals anchored in three-dimensional graphene gel network and the polyacrylamide layers could effectively prevent the agglomeration of Sn O₂ nanocrystals in the high current density.A capacity retention of over 90%after 300 cycles of 376 m Ah g^-1 was achieved at a current density of 5 A g^-1.In addition,a stable capacity of about 989 m Ah g^-1 at low current density of0.2 A g^-1 was achieved.In addition,alternatives to LIBs such as sodium-ion batteries?SIBs?and potassium-ion batteries?PIBs?are receiving burgeoning attention due to the low crustal abundance of lithium.Among them,PIBs are promising candidate because of the abundant resources,high working potential and fast kinetics.Particularly,alloy-based anodes have been widely studied owing to their high theoretical specific capacity.Although tin dioxide has been widely studied as anodes in LIBs,there are still few works about Sn O₂-based anodes in PIBs.For PIBs,based on that the performance of nano-materials is strongly depended on the scale size of particles,we have successfully synthesized Sn O₂ nanocrystals with a homogeneous size of 2-6 nm/porous carbon composite material via a facile two-step hydrothermal method.The composite exhibits excellent electrochemical performance which can be attributed to the well-defined porous carbon matrix and the well-restrained nano-scale Sn O₂ nanocrystals.Especially,the anode maintains a high reversible capacity of 108.3 m Ah g^-1?based on the total mass of the composite?even after 10000 cycles at a current density of 1 A g^-1.