在镍钴铝酸锂正极材料Li[Ni_0.8Co_0.15Al_0.05]O₂(NCA)制备过程中表面遗留的碱性物质会严重影响其循环稳定性能，针对这一难题，提出使用Y(PO₃)₃对其进行表面包覆改性，利用Y(PO₃)₃与表面残留的LiOH反应消除表面残碱，并探讨包覆改性对NCA整体性能的影响机制。测试分析结果表明，在低温煅烧过程中前驱体表面会形成均匀致密的Y(PO₃)₃和LiPO₃包覆层，LiPO₃有较高的离子电导率，双包覆层能够防止活性物质在电化学循环过程中与电解液相互接触时发生有害副反应，提高电极材料的循环稳定性。其中Y(PO₃)₃包覆量(质量分数)为1%的样品在0.1C下的首次库仑效率从未改性样品的78.65%提高到88.50%，在1C下循环150圈后容量保持率从59.38%提高到85.33%，相比于未改性样品具有更高的首次库仑效率和更优异的循环性能。

The electronic structure, magnetic, and optical properties of two-dimensional(2D) GaSe doped with rare earth elements X (X=Sc, Y, La, Ce, Eu) were calculated using the first-principles plane wave method based on density functional theory. The results show that intrinsic 2D GaSe is a p-type nonmagnetic semiconductor with an indirect bandgap of 2.661 1 eV. The spin-up and spin-down channels of Sc-, Y-, and La-doped 2D GaSe are symmetric, they are non-magnetic semiconductors. The magnetic moments of Ce- and Eu- doped 2D GaSe are 0.908μ_B and 7.163μ_B, which are magnetic semiconductors. Impurity energy levels appear in both spin-up and spin-down channels of Eu-doped 2D GaSe, which enhances the probability of electron transition. Compared with intrinsic 2D GaSe, the static dielectric constant of the doped 2D GaSe increases, and the polarization ability is strengthened. The absorption spectrum of the doped 2D GaSe shifts in the low-energy direction, and the red-shift phenomenon occurs, which extends the absorption spectral range. The optical reflection coefficient of the doped 2D GaSe is improved in the low energy region, and the improvement of Eu-doped 2D GaSe is the most obvious.