Sodium-ion batteries (SIBs) are considered to be promising alternatives to lithium-ion batteries (LIBs) due to the greater natural abundance of sodium raw materials versus lithium raw materials. However, to date, the plating and stripping mechanism of Na metal in full SIBs, which is one of the functional reactions in SIBs, has yet to be clarified. Herein, we systematically investigate the influence of current density on the nature of Na-metal deposition in a full-cell SIB using a three-electrode system composed of a commercial NaNi_1/3Fe_1/3Mn_1/3O₂ (NFM) cathode, a hard carbon (HC) anode, and a Na-metal reference electrode. Using electrochemical methods and ex situ electron microscopy, it is found that the deposition of Na metal increases with increasing current and plates on the HC anode in a spherical shape; the above morphology is in contrast to the dendrite-like morphology of Li plated onto graphite. Using first-principles calculations, it is discovered that the suppression of dendrite growth on SIB anodes can be attributed to the homogeneous adsorption energy of Na atoms on different facets of a sodium crystal.

钠离子电池（SIB）被认为是锂离子电池（LIB）的有前途的替代品，因为钠原料比锂原料具有更大的自然丰度。然而，迄今为止，尚未阐明全SIB中Na金属的镀覆和剥离机理，这是SIB中的功能反应之一。在本文中，我们使用由商用NaNi _1/3 Fe _1/3 Mn _1/3 O ₂组成的三电极系统，系统地研究了电流密度对全电池SIB中钠金属沉积性质的影响。（NFM）阴极，硬碳（HC）阳极和钠金属参比电极。使用电化学方法和非原位电子显微镜观察发现，Na金属的沉积随着电流的增加而增加，并且在HC阳极上呈球形的镀层增加；上述形态与镀在石墨上的Li的树突状形态相反。使用第一性原理计算，发现抑制SIB阳极上的枝晶生长可以归因于钠原子在钠晶体不同面上的均匀吸附能。