  We consider Einstein-Horndeski-Maxwell gravity, together with a cosmological
constant and multiple Horndeski axions. We construct charged AdS planar black
holes in general dimensions where the Horndeski anxions span over the planar
directions. We analyse the thermodynamics and obtain the black hole volumes. We
show that the reverse isoperimetric inequality can be violated, implying that
these black holes can store information more efficiently than the Schwarzschild
black hole.
