Next-generation non-volatile memories with ultrafast speed, low power consumption, and high density are highly desired in the era of big data. Here, we report a high performance memristor based on a Ag/BaTiO 3 /Nb:SrTiO 3 ferroelectric tunnel junction (FTJ) with the fastest operation speed (600 ps) and the highest number of states (32 states or 5 bits) per cell among the reported FTJs. The sub-nanosecond resistive switching maintains up to 358 K, and the write current density is as low as 4 × 10 3 A cm −2. The functionality of spike-timingdependent plasticity served as a solid synaptic device is also obtained with ultrafast operation. Furthermore, it is demonstrated that a Nb:SrTiO 3 electrode with a higher carrier concentration and a metal electrode with lower work function tend to improve the operation speed. These results may throw light on the way for overcoming the storage performance gap between different levels of the memory hierarchy and developing ultrafast neuromorphic computing systems.

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Epoxy resins with high thermal and mechanical performance as well as good resistance to fire are difficult to synthesize. In this work, a high-performance intrinsically flame-retardant epoxy resin (diglycidyl ether of daidzein (DGED)) was synthesized from renewable daidzein using an efficient one-step process, without the addition of additional flame retardants. The structure of DGED was confirmed by Fourier transform infrared (FTIR), 1 H NMR, and 13 C NMR before it was cured with 4,4′diaminodiphenylmethane (DDM). A commercial diglycidyl ether of bisphenol A (DGEBA) was cured with the same curing agent. Results indicated that the cured DGED/DDM system possessed glass transition temperature (T g ) of up to 205 °C (172 °C for DGEBA/DDM), and tensile strength, tensile modulus, flexural strength, and flexural modulus of 83, 2972, 131, and 2980 MPa, respectively, all much higher than those of cured DGEBA/DDM. The cured DGED/DDM system demonstrated excellent flame-retardant properties, showing a residual char of 42.9% at 800 °C, limiting oxygen index (LOI) of 31.6%, and flammability rating of V-0 in UL94 test. This work provides us an efficient method to prepare high-performance epoxy resin from renewable resource.