This paper presents an implicit solvation model integrated into the widely used density-functional theory (DFT) code VASP. The model is based on joint density functional theory and accounts for electrostatic, cavitation, and dispersion effects in solvation. The model is implemented in VASP, a plane-wave DFT code, and provides a computationally efficient and accurate way to study solvation effects on molecular and extended systems. The model is validated by comparing results with those from the JDFTx code and experimental data. The solvation model is applied to study the surface energies of different facets of semiconducting and metallic nanocrystals and the S_N2 reaction pathway. The results show that solvation reduces the surface energies of nanocrystals, especially for semiconducting ones, and increases the energy barrier of the S_N2 reaction. The model is also applied to study the effect of solvents on the surface energies of nanocrystal facets and the energy barrier for the nucleophilic substitution reaction of chloromethane. The results are in good agreement with previous calculations. The model is capable of handling large periodic systems and is interoperable with standard pseudopotential libraries. The software is freely available as a patch to the original VASP code. The model is validated by comparing the solvation energies of several molecules with experimental results and the JDFTx code. The results show that the model is accurate and efficient for studying solvation effects in nanocrystal surfaces and reaction pathways.This paper presents an implicit solvation model integrated into the widely used density-functional theory (DFT) code VASP. The model is based on joint density functional theory and accounts for electrostatic, cavitation, and dispersion effects in solvation. The model is implemented in VASP, a plane-wave DFT code, and provides a computationally efficient and accurate way to study solvation effects on molecular and extended systems. The model is validated by comparing results with those from the JDFTx code and experimental data. The solvation model is applied to study the surface energies of different facets of semiconducting and metallic nanocrystals and the S_N2 reaction pathway. The results show that solvation reduces the surface energies of nanocrystals, especially for semiconducting ones, and increases the energy barrier of the S_N2 reaction. The model is also applied to study the effect of solvents on the surface energies of nanocrystal facets and the energy barrier for the nucleophilic substitution reaction of chloromethane. The results are in good agreement with previous calculations. The model is capable of handling large periodic systems and is interoperable with standard pseudopotential libraries. The software is freely available as a patch to the original VASP code. The model is validated by comparing the solvation energies of several molecules with experimental results and the JDFTx code. The results show that the model is accurate and efficient for studying solvation effects in nanocrystal surfaces and reaction pathways.