Na-ion batteries (NIBs) have attracted increasing attention given the fact that sodium is relatively more plentiful and affordable than lithium for sustainable and large-scale energy storage systems. However, the shortage of electrode materials with outstanding comprehensive properties has limited the practical implementations of NIBs. Among all the discovered anode materials, transition-metal sulfide has been proven as one of the most competitive and promising ones due to its excellent redox reversibility and relatively high theoretical capacity. In this study, double-morphology N-doped CoS/multichannel carbon nanofibers composites (CoS/MCNFs) are precisely designed, which overcome common issues such as the poor cycling life and inferior rate performance of CoS electrodes. The conductive 3D interconnected multichannel nanostructure of CoS/MCNFs provides efficient buffer zones for the release of mechanical stresses from Na ions intercalation/deintercalation. The synergy of the diverse structural features enables a robust frame and a rapid electrochemical reaction in CoS/MCNFs anode, resulting in an impressive long-term cycling life of 900 cycles with a capacity of 620 mAh g at 1 A g (86.4% theoretical capacity) and a surprisingly high-power output. The proposed design in this study provides a rational and novel thought for fabricating electrode materials.

Separators are vital parts of all lithium-ion batteries (LIBs), and they play a critical role in their thermal safety and electrochemical performance. Considering the low thermal stability and inferior electrolyte wettability of commercial polyolefin membranes, in this study, a novel thermotolerant polyimide aerogel (PIA) separator is designed. This is the first report on the use of chemically cross-linked PIA separators for LIBs. The outstanding porosity (78.35%) and electrolyte absorption (321.66%) of PIA separators contribute to the low internal resistance and outstanding electrochemical performance of LIBs, which can retain a high specific capacity of 118 mAh g −1 after 1000 cycles at a current density of 1 C. In addition, The LiFePO 4 |Li metal batteries with PIA separators are extremely stable at 90 °C (>300 cycles), and maintain stability even at 120 °C. More importantly, for pouch batteries, PIA separators result in higher thermal runaway temperatures compared with Celgard separators. In this paper, the pyrolysis mechanism and thermodynamic process of PIA separators are clarified by DFT calculations and in situ synchrotron vacuum UV photoionization mass spectrometry experiments.

Polyhedral carbon-coated structural N-CoS2@C nanoparticles are synthesized by a facile one-pot solvothermal technique and exhibit excellent sodium ion storage performance.

Advanced thermal insulation materials with low thermal conductivity and robustness derived from regenerative resources are badly needed for building energy conservation. Among them, nanofibrillated cellulose aerogels have huge application potential in the field of thermal insulation materials, but it is still a challenge to prepare cellulose aerogels of excellent comprehensive properties in a simple way. Herein, we demonstrate a unidirectional freeze-drying strategy to develop a novel “robust–soft” anisotropic nanofibrillated cellulose aerogel (NFC-Si-T) by integrating nanofibrillated cellulose (NFC) and Si–O–Si bonding networks under the catalytic dehydration of p-toluenesulfonic acid (TsOH). The anisotropic structure endows the NFC-Si-T with high flexibility that can be easily bent or even tied with a knot, and in addition, it possesses high Young’s modulus (1–3.66 MPa) that can resist the compression weight of 10,000 times of its own weight without deformation. Furthermore, the NFC-Si-T aerogels exhibit anisotropic thermal insulation performances with a low average thermal conductivity (0.028–0.049 W m–1 K–1). More importantly, the limited oxygen index of the NFC-Si-T reaches up to 42.6–51%, showing excellent flame-retardant performance. Therefore, the “robust–soft” anisotropic NFC-Si-T aerogels can be used as an advanced thermal insulation material for building thermal insulation applications.

Polyimide aerogels were prepared using low-cost polymers with different structure capped polyamide oligomers serving as cross-linking agents.