Contrary to the semiconductor industry, with thin finely polished single crystalline wafers, processing of polycrystalline material would be preferred for battery purposes to keep costs low and production volume high. This means grain boundaries and natural defects need to be kept in mind. A shallow implantation depth can run into orientation effects, leading to an inhomogeneous implantation profile similar to the implantation into nonplanar semiconductors. A defect which extends past the implanted zone can also be filled with lithium and bypass the deflective properties from the stress field generated by the implanted ions.