Get Finer Grid with respect to x using NDSolve in Mathematica

I use Mathematica NDSolve to numerically solve V(x,t) and export the numerical values of V(x,t) at each x and t into an external csv file. I find Mathematica only numerically give results with step size of 1 in both x and t. However, I want a finer grid of the numerical results, for example, 0, 0.01, 0.02, … , M in the x-dimension. I tried to add MaxStepSize→0.1 in the NDSolver, but it gives errors and seems not solving finer grid of x in the csv file. NDSolve::ndsz: At t == 95.86748044587323, step size is effectively zero; singularity or stiff system suspected. >>

My question: what is the correct way to get numerical matrix on V(x,t) on a finer x? The relevant code is in export.nb

You're exporting the data1 table to your spreadsheet, so that's where you'll need to request the additional sample points. Something like this should work:
data1=Table[Evaluate[v[t,x]/.s],{t,0,T},{x,0,M,0.1}]
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