| Tin-based materials are one of the most promising high-performance anode materials for lithium-ion batteries due to their high theoretical specific capacity,moderate deintercalation potential and low price.At the same time,tin based anode is also the first commercial non-carbon anode material.In 2005,Sony launched the"Nexelion"battery with amorphous Sn-Co-C ternary alloy as the negative electrode.Compared with the traditional lithium battery with same model,the volumetric capacity of the"Nexelion"battery is increased by 30%but it could only maintain only 60%capacity retention rate after 300 cycles.In recent years,there is rising demand for lithium-ion batteries with high energy density and high safety.To meet these requirements,all-solid-state batteries,which have wide electrochemical window,low flammability and low volatility,are necessary to assemble with high-performance anode.In this paper,two kinds of Sn-Fe(-C)anode materials were prepared by high energy ball milling and magnetron sputtering.Otherwise,Li-Snwas used as a novel filler to modify PEO-based solid electrolyte.The further study on the performance of as-prepared anode materials in half/full cell with liquid electrolyte and solid-state battery were carried out.The main phases of Sn-Fe-C anode material prepared by pendulum ball milling are Sn2Fe and Sn,which are uniformly distributed on the graphite substrate.The ICE of as-milled Sn-Fe-C materials can reach 80.1%.It can cycle stably in 900 cycles with the current density of 200mA g-1 and reversible capacity of 627.9 mAh g-1.The capacity retention is 85.6%after cycling.Layered Sn-Fe-C/C obtained by magnetron sputtering showed better cycle stability and coulombic efficiency than Sn-Fe film.It can run for 200 times with capacity retention of 98.1%under the current density of 400 mA g-1,and 800 times with reversible specific capacity of 608.3mA h g-1 under the current density of 2 A g-1.The high-current cycling stability of the ball milled Sn-Fe-C powder material was optimized.By adding high-performance conductive agent SWCNTs and binder additive acrylonitrile copolymer(LA)into the slurry,the cycle stability of the negative electrode was significantly improved at a current density of 1 A g-1.The capacity retention of anode with SWCNTs increased from 24.2%to 76.6%after 600 cycles.When LA was added,the capacity retention rate reached 98.4%after 1000 cycles.With the addition of both SWCNTs and LA,the anode can stably cycle for more than 800 cycles at a specific capacity higher than 443.6 mA h g-1 at a high current density of 2 A g-1.Furthermore,the ball-milled Sn-Fe-C material and commercial LFP cathode material were assembled to explore the full battery performance of the anode.The results show that the coulombic efficiency is remarkably improved by adjusting the cycling voltage window of the anode material.The corresponding full cell can release the specific capacity of 496.4 mA h g-1 after 50 cycles at a current density of 200 mA g-1.When cycling at a current density of 1 A g-1,it can stably run for more than 350 tims with a specific capacity of293.7 mA h g-1,and the coulombic efficiency remains at 99.45%.PEO-based electrolyte was modified with Li22Sn5 alloy as inorganic filler,and the content of crystalline phase in PEO decreased significantly.When the amount of addition was 10 wt%,the ionic conductivity of PEO-Li22Sn5 composite solid electrolyte reached the highest to 1.0×10-4S cm-1 at 40?.PEO-10%Li22Sn5 electrolyte and Snfilm,SnO2film,Sn-Fe film anode were assembled respectively for solid-state half cell.Sn-Fe film anode has the best cycle stability,which proves the effective function of transition metal element Fe on improving the cyclic stability of Sn-based anode materials in solid-state batteries.The ball milled Sn-Fe-C material was also assembled into solid-state half cell.The battery can stably cycle for more than 15 times at 100 mA g-1 and maintain a specific capacity that is over 580.8 mA h g-1. |
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