All-solid-state lithium secondary batteries have never shown both higher energy and power density than them of conventional lithium-ion batteries. Herein, on the basic of well-established percolation theory, we expected what includes a dimension-controlled solid electrolyte in an electrode can improve the electrochemical properties, such as ionic conduction and capacity retention. The behavior of electrodes is systematically demonstrated via computational simulations of virtual electrodes with various dimension-controlled solid electrolytes. In particular, the effective ionic conductivity and the specific contact area are investigated as key parameters that determine cell performance. We confirmed that the dimension-controlled solid electrolyte can improve the electrochemical performance of all-solid-state batteries by enhancing the effective ionic conductivity, which is facilely realized via percolation of the solid electrolyte with an increased dimensional geometry. This simulation prediction suggests a clue to be able to overcome poor performance of present all-solid-state batteries.