  Lithium chloride water solution is a good option for solar neutrino
detection. The $\nu_e$ charged-current (CC) interaction cross-section on
$\rm{{}^{7}Li}$ is evaluated with new B(GT) experimental measurements. The
total CC interaction cross-section weighted by the solar $^8$B electron
neutrino spectrum is $3.759\times10^{-42} \rm{cm}^2$, which is about 60 times
that of the neutrino-electron elastic scattering process. The final state
effective kinetic energy after the CC interaction on $\rm{{}^{7}Li}$ directly
reflects the neutrino energy, which stands in sharp contrast to the plateau
structure of recoil electrons of the elastic scattering. With the high
solubility of LiCl of 74.5 g/100 g water at 10$^\circ$C and the high natural
abundance of 92.41%, the molarity of $\rm{{}^{7}Li}$ in water can reach 11
mol/L for safe operation at room temperature. The CC event rate of $\nu_e$ on
$\rm{{}^{7}Li}$ in the LiCl water solution is comparable to that of
neutrino-electron elastic scattering. In addition, the $\nu_e$ CC interaction
with the contained $\rm{{}^{37}Cl}$ also contributes a few percent of the total
CC event rate. The contained $\rm{{}^{35}Cl}$ and $\rm{{}^{6}Li}$ also make a
delay-coincidence detection for electron antineutrinos possible. The
recrystallization method is found to be applicable for LiCl sample
purification. The measured attenuation length of $11\pm1$ m at 430 nm shows
that the LiCl solution is practicable for a 10-m diameter detector for solar
neutrino detection. Clear advantages are found in studying the upturn effect of
solar neutrino oscillation, light sterile neutrinos, and Earth matter effect.
The sensitivities in discovering solar neutrino upturn and light sterile
neutrinos are shown.
