Fig. 2: Phase transition correlating electrochemical memory and electric-to-chemical energy conversion.

a Schematic of the ECRAM structure. b Conductance modulation under long-term gate current bias. c, Retention of 9 programmed analog states (V_d = 3 V) without gate bias, and the corresponding coefficient of variation \({c}_{{\mbox{v}}}\). d Schematic of the on-chip electrochemical measurement setup and proposed reactions. e The I-V curves for Pt (top) and MoO_x (bottom) as a function of the test times. f Tafel slopes as a function of the test times. g Reaction pathway and free energy diagram for ECRAM and electrocatalysis. h The mechanisms of HER and the ECRAM based on proton intercalation, sharing the proton migration, adsorption and intercalation process. i Correlation between conductance and proton flux Q_H in ECRAM and electrocatalysis devices, with the dashed line as the guide to the eye. The ECRAM data dots with the same colors were obtained by applying the same amplitude of gate current with various pulse amounts, and the electrocatalysis data dots were obtained from the data in (e). Some representative data from previous studies are used for comparison. In the background shadow, light red represents the energy conversion region, light blue represents the memory region, and light gray represents the electrochemically inert region.