Isotropy‐Induced Stress Relaxation and Strong‐Tolerance for High‐Rate and Long‐Duration Sodium Storage by Amorphous Structure Engineering

Abstract

High-performance conversion-reaction-based electrodes have received enormous attention due to their high theoretical capacities, yet the poor structural stability and large stress accumulation induced from volume change are identified as major limiting factors for further utilization. Although viable strategies are exerted to acquire durable storage capacity, the controllable technology of inner stress is still required to explore. Herein, the amorphous structured GeS 2 with 2D porous sheet morphology is designed for sodiumion batteries (SIBs). The differences in reaction mechanism and structure reversibility between amorphous and crystalline states are systematically investigated and unraveled. Notably, the amorphous matrix can ensure evenly distributed intermediate interface and alleviated aggregation of active materials, promoting the complete conversion reaction with decreased hysteresis. Furthermore, it provides more isotropic Na-ion diffusion channels and active sites, effectively boosting the reaction kinetics. Meanwhile, it can fully relieve the volume expansion and restrain the inner stress of GeS 2 , resulting in excellent structural tolerance. As expected, it expresses prominent rate capability and cyclic life (512.8 mA h g −1 at a superhigh rate of 10 A g −1 after 1000 cycles) for SIBs. Therefore, amorphization engineering is a reliable strategy to obtain the robust framework and unimpeded diffusion channels for developing highperformance conversion-reaction-based electrode materials.

Aliovalent doping engineering enables multiple modulations of FeS2anodes to achieve fast and durable sodium storage

“…Generally, EIS patterns consist of a semicircle in the high-frequency region and a straight line at low frequency, which are associated with the charge transfer resistance and Warburg diffusion process, respectively. 36,49,50 As shown in Fig. 4e, the P–FeS 2 @C electrode exhibits a smaller semicircle than that of the undoped FeS 2 @C, which demonstrates that it possesses a smaller charge transfer resistance.…”

Unlocking the Potential of Vanadium Oxide for Ultrafast and Stable Zn2+ Storage Through Optimized Stress Distribution: From Engineering Simulation to Elaborate Structure Design

“…A higher discharge plateau and lower polarization of VO-NS cathode at 1 A g −1 are observed in the charge/discharge curves (Figure 3d), which indicated the lower structural stress and Zn 2+ diffusion barrier in VO-NSs. [23,39] Large current densities could arouse enhanced surface structural stress, resulting in a reduction in capacity. [23,40] As shown in Figure 3e, the VO-NS cathode delivers discharge capacities of 382, 372, 357, 342, 320, 300, 275, 250, and 233 mAh g −1 at the current densities of 0.5, 1, 2, 5, 10, 20, 30, 50, and 70 A g −1 , respectively.…”

“…[23,39] Large current densities could arouse enhanced surface structural stress, resulting in a reduction in capacity. [23,40] As shown in Figure 3e, the VO-NS cathode delivers discharge capacities of 382, 372, 357, 342, 320, 300, 275, 250, and 233 mAh g −1 at the current densities of 0.5, 1, 2, 5, 10, 20, 30, 50, and 70 A g −1 , respectively. Even at the ultrahigh current density of 100 A g −1 , an impressive capacity of 222 mAh g −1 can still be preserved.…”

“…[1][2][3] Zn-based batteries are promising for commercialization due to their high theoretical capacity (820 mAh g −1 ), relatively high Zn binder and the current collector, which will lead to the fading in capacity. [22][23][24] In addition, such stress can also change the reaction driving force and weaken the reaction rate. [24] Hwang et al showed that the Li + diffusion in Fe 3 O 4 films can arouse unexpected strains and cause mechanical and contact failures.…”

Entropy‐Change Driven Highly Reversible Sodium Storage for Conversion‐Type Sulfide

“…As expected, for the primary sample, the cation valences are Cu 1+ , Mn 2+ , Fe 2+ , Sn 2+/4+ , and Ge 2+/4+ , respectively. Once discharged to 0.01 V, the Cu 2p, Fe 2p, Mn 2p, Sn 3d, and Ge 3d spectra showed clear signs of reduction of Cu 1+ to Cu 0 (931.03 and 951.01 eV), [26] Mn 2+ to Mn 0 (641.03 and 652.70 eV), [27] Fe 2+ to Fe 0 (720.72 eV), [28] Sn 2+/4+ to Sn 0 (485.13 eV) [29] and Ge 2+/4+ to Ge 0 (30.12 eV), [30] indicative of the reduction of all the multivalent cations to M 0 in the HE-CMFSGS lattice. The binding energies returned to the original values when it was recharged to 3.0 V, which suggests a reversible structural conversion in the HE-CMFSGS crystallite.…”