Li-metal batteries have been emerging as attractive technologies for electrical energy storage and conversion by virtue of the ultrahigh theoretical specific capacity of lithium. However, the undesirable Li-dendrite growth upon prolonged cycling gives rise to thermal runaway, inducing tremendous safety concerns that impede the development of the technology. In general, Li nucleation and growth behavior significantly changes when the operating condition is modified through modulating temperature or thermodynamic energy to produce regulated lithium depositions. Herein, this perspective takes these two key factors as an example to emphasize the importance of thermodynamic understandings of the Li-dendrite issue. The key challenges and corresponding strategies for designing advanced dendrite-free Li-metal anodes with respect to thermodynamic factors are also discussed as fundamental guidance for future development.