Rational design of heterogeneous electrode materials with hierarchical architecture is a potential approach to significantly improve their energy densities. Herein, we report a tailored microwave-assisted synthetic strategy to create heterogeneous hierarchical Ti₃SiC₂@C-containing Na₂Ti₇O₁₅ (MAX@C-NTO) composites as potential anode materials for high-performance sodium storage in a wide temperature range from 25 to 80 °C. This composite delivers first reversible capacities of 230 mAh g^–1 at 200 mA g^–1 and 149 mAh g^–1 at 3000 mA g^–1 at 25 °C. A high capacity of ∼93 mAh g^–1 without any apparent decay even after more than 10 000 cycles is obtained at an ultrahigh current density of 10 000 mA g^–1. Moreover, both a high reversible capacity and an ultralong durable stability are achieved below 60 °C for the same composites, wherein a 75.2% capacity retention (∼120 mAh g^–1 at 10 000 mA g^–1) is achieved after 3000 cycles at 60 °C. To the best of our knowledge, both the sodium storage performances and the temperature tolerances outperform those of all the Ti-based sodium storage materials reported so far. The superior sodium storage performances of the as-synthesized composites are attributed to the heterogeneous core–shell architecture, which not only provides fast kinetics by high pseudocapacitance but also prolongs cycling life by preventing particle agglomeration and facilitates the transportation of electrons and sodium ions by large micro/mesopore structure.

中文翻译：

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Ti ₃ SiC ₂ @C含Na ₂ Ti ₇ O ₁₅异质结构，用于高温下的高性能钠存储

具有分层结构的异质电极材料的合理设计是一种显着提高其能量密度的潜在方法。在此，我们报告了一种量身定制的微波辅助合成策略，以创建异质分层Ti ₃ SiC ₂ @C的Na ₂ Ti ₇ O ₁₅（MAX @ C-NTO）复合材料，作为在宽范围内高性能钠存储的潜在阳极材料。温度范围为25至80°C。这种复合材料在25°C时在200 mA g ^–1时具有230 mAh g ^–1的首次可逆容量，在3000 mA g ^–1时具有149 mAh g ^–1的可逆容量。约93 mAh g ^–1的高容量在10 000 mA g ^–1的超高电流密度下，即使经过10000次以上的循环，也没有任何明显的衰减。此外，同时具有高可逆容量和超长耐久稳定性得以实现低于60℃对于相同的复合材料，其特征在于，75.2％的容量保持率（~120毫安克^-1在10000毫安克^-1）是在60°C下经过3000次循环后达到的。据我们所知，钠存储性能和温度容限均优于迄今为止报道的所有Ti基钠存储材料。合成后的复合材料具有优异的钠存储性能，这归因于其异构的核-壳结构，不仅通过高假电容提供了快速的动力学，而且还通过防止颗粒团聚延长了循环寿命，并促进了电子和钠离子的大范围运输。微孔/中孔结构。