Development of the anode for a lithium-ion battery based on nanoporous germanium formed by the implantation with silver ions

In this work, the possibility of using a nanoporous Ge layer ($p$-Ge), formed by implantation with Ag$^+$ ions on a single crystal $c$-Ge substrate, as an anode electrode for a lithium-ion battery was studied. For this, the ion implantation of $c$-Ge substrutes was carried out at an energy of $E$ = 30 keV, a current density of $J$ = 5 $\mu$A/cm$^2$, and a dose of $D$ = 1.3$\cdot$10$^{16}$ ion/cm$^2$. It was shown that the obtained spongy Ag:$p$-Ge layers, consisting of intertwining Ge nanowires, demonstrate a high Coulomb efficiency ($>$ 97%) after the first cycle and show up to 79.5% of reversible capacity after 1000 cycles.