  In this paper, we investigate the combined effects of the cloud of strings
and quintessence on the thermodynamics of a Reissner-Nordstr\"om-de Sitter
black hole. Based on the equivalent thermodynamic quantities considering the
correlation between the black hole horizon and the cosmological horizon, we
extensively discuss the phase transitions of the space-time. Our analysis prove
that similar to the case in AdS space-time, second-order phase transitions
could take place under certain conditions, with the absence of first-order
phase transition in the charged de Sitter black holes with cloud of string and
quintessence. The effects of different thermodynamic quantities on the phase
transitions are also quantitatively discussed, which provides a new approach to
study the thermodynamic qualities of unstable dS space-time. Focusing on the
entropy force generated by the interaction between the black hole horizon and
the cosmological horizon, as well as the Lennard-Jones force between two
particles, our results demonstrate the strong degeneracy between the entropy
force of the two horizons and the ratio of the horizon positions, which follows
the surprisingly similar law given the relation between the Lennard-Jones force
and the ratio of two particle positions. Therefore, the study of the entropy
force between two horizons, is not only beneficial to the deep exploration of
the three modes of cosmic evolution, but also helpful to understand the
correlation between the microstates of particles in black holes and those in
ordinary thermodynamic systems.
