高性能锂离子电池硼掺杂硅纳米棒阳级

B-doped Silicon Nanorods Anode for High-performance Lithium-ion Battery

高容量锂离子电池硅阳极面临的最大挑战就是循环过程中大体积变化导致的硅颗粒粉化和本身低电导率,致使电池容量急速衰减、循环稳定性差。硼掺杂对提高锂离子电池硅阳极的电导率和电化学性能起着至关重要作用。通过熔铸铝硅和铝硼中间合金-酸蚀铝-包覆碳化工艺,成功合成硼掺杂微米级硅纳米棒包覆碳(B-Si@C)锂离子电池阳极材料。硼掺杂一方面提高硅的导电性,同时有助于硅的晶格错排、产生大量位错、挛晶、层错晶体缺陷,这将使电池循环过程中塑性流动提前发生,有效提高硅纳米棒的抗粉化能力。这种富含缺陷的 B-Si@C 纳米棒阳极具有560mAhg可逆比容量,能稳定循环500次,首次库伦效率高达90.6%、倍率性能良好。

The biggest challenge of the silicon anode of the high-capacity lithium-ion batteries(LIBs)is the large change of volume in the circulation process and low conductivity itself causing the rapid attenuation of the battery capacity.Boron doping plays a crucial role in improving the electrical conductivity and electrochemical properties of the silicon anode for LIBs.Boron-doped micron-grade silicon nanorods-coated carbon(B-Si@C)anode composite was successfully synthesized by casting Al-Si and Al-B intermediate alloys,acid etching Al and PDA carbonization process.B doping not only improves the conductivity of silicon,but also helps the lattice misarrangement to produce a large number of crystal defects,which will make the plastic flow occur in advance during the battery cycle and effectively improve the cycling stability of silicon anodes.The defect-rich B-Si@C nanorod anode has a high reversible specific capacity of 560mAhg,and enables stable cycles of 500times,with the first Coulombic efficiency of up to 90.6%and good rate capability.