Dendrite growth of metal anodes is one of the key hindrances for both secondary aqueous metal batteries and nonaqueous metal batteries. In this work, a freestanding Ti3C2T x MXene@Zn paper is designed as both zinc metal anode and lithium metal anode host to address the issue. The binder-free Ti3C2T x MXene@Zn paper exhibits merits of good mechanical flexibility, high electronic conductivity, hydrophilicity, and lithiophilicity. The crystal growth mechanism of Zn metal on common Zn foil and Ti3C2T x MXene@Zn composite is also studied. It is found that the Ti3C2T x MXene@Zn paper can effectively suppress the dendrite growth of Zn, enabling reversible and fast Zn plating/stripping kinetics in an aqueous electrolyte. Moreover, the Ti3C2T x MXene@Zn paper can be used as a 3D host for a lithium metal anode. In this host, Zn is utilized as a nucleation agent to suppress the Li dendrite growth. The freestanding Ti3C2T x MXene@Zn@Li anode exhibits superior reversibility with high Coulombic efficiency (97.69% over 600 cycles at 1.0 mA cm–2) and low polarization compared with the Cu@Li anode. These findings may be useful for the design of dendrite-free metal-based energy storage systems.

Silicon has been developed as the exceptionally desirable anode candidate for lithium-ion batteries (LIBs), attributing to its highest theoretical capacity, low working potential, and abundant resource. However, large volume expansion and poor conductivity hinder its practical application. Herein, we fabricate flexible, freestanding, and binder-free silicon/MXene composite papers directly as anodes for LIBs. The Silicon/MXene composite papers are synthesized via covalently anchoring silicon nanospheres on the highly conductive networks based on MXene sheets by vacuum filtration. This unique architecture can accommodate large volume expansion, enhance conductivity of composites, prevent restacking of MXene sheets, offer additional active sites, and facilitate efficient ion transport, which exhibits superior electrochemical performance with a high capacity of 2118 mAh•g −1 at 200 mA•g −1 current density after 100 cycles, a steady cycling ability of 1672 mAh•g −1 at 1000 mA•g −1 after 200 cycles, and a rate performance of 890 mAh•g −1 at 5000 mA•g −1 . This work may shed lights on the development of silicon-based anodes for LIBs.

Potassium-ion batteries (KIBs) are considered favorable candidates for post-lithium-ion batteries, a quality attributed to their low cost, abundance as a resource, and high working potential (−2.93 V for K + /K). Owning to its relatively low potassiation potential and high theoretical capacity, antimony (Sb) is one of the most favorable anodes for KIBs. However, the large volume changes during K−Sb alloying and dealloying causes fast capacity degradation. In this report, nanoporous Sb (NP-Sb) is fabricated by an environmentally friendly vacuum-distillation method. The NP-Sb is formed via evaporating low-boiling-point zinc (Zn). The byproduct Zn can be recycled. It is further found that the morphology and porosity can be controlled by adjusting Zn−Sb composition and distillation temperature. The nanoporous structure can accommodate volume expansion and accelerate ion transport. The NP-Sb anode delivers an improved electrochemical performance. These results suggest that the vacuum-distillation method may provide a direction for the green, large-scale, and tunable fabrication of nanoporous materials.

Rechargeable zinc (Zn)-ion batteries are regarded as highly prospective candidates for next-generation renewable and safe energy storage systems. However, the uncontrolled dendrite growth of the Zn anode impedes their practical application. Here, a scalable and controllable approach is developed for converting commercial titanium (Ti) foil to 3D porous Ti, which retains good resistance to corrosion, high electrical conductivity, and excellent mechanical properties. Benefiting from a spontaneous ultrathin zincophilic titanium dioxide (TiO2) interfacial layer and continuous 3D structure, the 3D porous Ti can act as an effective host to achieve a 3D Ti/Zn metal anode. By ensuring homogeneous nucleation, uniform current distribution, and volume change accommodation, the dendritic growth of 3D Ti/Zn metal anode is effectively inhibited with stable Zn plating/stripping up to 2000 h with low polarization. When conjugated with a 3D sulfur-doped Ti3C2T x MXene@MnO2 nanotube cathode, a high rate and stable Zn cell is achieved with 95.46% capacity retention after 500 cycles at a high rate of 5 A g–1. This work may also be interesting for researches in porous metals and other battery systems.

Owing to its high theoretical capacity, appropriate working potential, abundant resource, intrinsic safety, and low cost, zinc (Zn) metal is regarded as one of the most promising anode candidates for aqueous batteries. However, the hazards caused by dendrite growth and side reactions impede its practical applications. Herein, to solve these problems, a protective heterogeneous layer composed of electronic conductive sulfur-doped three-dimensional (3D) MXene and ionic conductive ZnS on Zn anode is designed and constructed. The sulfur doping and the creation of a 3D structure on MXene are simultaneously achieved during the generation of ZnS. The sulfur-doped 3D MXene can effectively homogenize distribution of electric field, decrease local current density, and alleviate volume change. The ZnS can inhibit side reactions, promote uniform Zn2+ distribution, and accelerate Zn2+ migration. Consequently, a stable and dendrite-free Zn anode is achieved with notable cycling stability up to 1600 h and rate performance. The relationship between structure of protective layer and performance of Zn anode is also probed. With the protected Zn anode and freestanding sulfur-doped 3D MXene@MnO2 cathode, a high-energy, long cycling life, and high-rate full cell is obtained. This work may provide a direction for the design of practical Zn anodes and other metal-based battery systems.