for electron and charge transfer. Therefore, the OV-T n QDs@ PCN/S cathode delivers a superb long-term cycling stability (88% capacity retention over 1000 cycles at 2C) under a S-mass loading of 2.2 mg cm −1 and an E/S ratio of 10 µL mg −1 . In addition, the cathode exhibits good Li + storage at high S-mass loading (4.8 mg cm −1 ) and lean electrolyte (E/S ratio: 4.5 µL mg −1 ), demonstrating its great potential for practical implementation. Our strategy may be extended to other MXenes (e.g., Ti 3 CNT x , Nb 2 CT x , and V 2 CT x ) and pave the way to realize the facile synthesis of QDs with rich OVs for advanced Li-S batteries.

Dissolution of lithium polysulfides (LiPSs), volume expansion, and the insulative nature of elemental sulfur are the major challenges for high-performance lithium sulfur batteries (LSBs). To mitigate these adverse effects, we developed a 3D MnO 2 nanosheets@delaminated-Ti 3 C 2 (MNSs@d-Ti 3 C 2 ) aerogel framework via an electrostatic self-assembly approach, which proves to be a good sulfur host for high-performance LSBs. In the MNS@d-Ti 3 C 2 aerogel, the high specific surface area and mesoporous structure benefit the high sulfur loading; the synergistic effect of the d-Ti 3 C 2 and the polar MnO 2 provides a robust conductive pathway and promotes the LiPSs' adsorption and thus can effectively facilitate electron transport and strengthen the capture ability to confine the LiPSs in the cathode. As a result, the cathode based on MNSs@d-Ti 3 C 2 /S composite exhibits a high active-sulfur utilization (initial discharge capacity of 1140 mA h g S −1), good rate capacity (reversible capacity of 615 mA h g S −1 at 2.0 C), outstanding specific discharge capacity, and superior capacity retention (only 0.06% capacity decay per cycle over 500 cycles at 1.0 C, even at sulfur loadings up to 3.7 mg cm −2 ).

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In this paper, we consider a state estimation problem. In this problem, a sensor measures the state of a linear discrete‐time system and sends measurements to an estimator via a packet‐dropping communication link. We are concerned with the effect of Denial‐of‐Service (DoS) attacks on stability of the estimation system, and particularly focus on how to examine whether the communication channel is under DoS attack or not as well as how to defend accordingly, if defense is possible. We formulate the detection problem as a hypothesis testing problem provided that the statistics of the communication channel is known a priori. Two defense countermeasures are proposed: one of which uses a secured packet coding approach to partly compensate the previous packet loss; and in the other the sensor's transmission power is raised to resist the jamming effect brought by the DoS attack. Simulations are provided to demonstrate the main results.

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