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Phosphides with high theoretical capacity are considered ideal anode materials for lithium‐ion capacitors (LICs), but poor electronic conductivity as well as unsatisfied cyclic stability limits the performance of the phosphides. Here a covalently bonded CoP@C heterostructure is reported, which consists of 5 nm CoP quantum dots (QDs) like pomegranate seeds pinned in carbon polyhedron through interfacial Co─P─C bonding. The ultrafine size of CoP QDs provides more reactive sites and a shorten electrons/ions diffusion path, boosting the specific capacity. The Co─P─C bond induces the energy band variation of CoP and increases the interfacial charge density, bringing about fast kinetics. Besides, the Co─P─C bond introduces a robust pining effect among CoP QDs and carbon polyhedra, greatly improving the structure stability of 5 nm CoP QDs. The CoP@C heterostructure electrode exhibits high capacity (nearly 1000 mAh g−1) and superior cycling stability. It is worth noting that a prototyped LIC full‐cell of YP80//CoP@C presents an impressive high energy density of 172 Wh kg−1 and a power density of 10.8 kW kg−1. Moreover, the LIC possesses an ultra‐long life, retaining 80% after 20,000 cycles. This study offers an effective design for phosphides achieving fast kinetics and superior structure stability through an interfacial bonding approach. [ABSTRACT FROM AUTHOR]

Black phosphorus (BP) has been recognized as an alluring fast‐charging anode for batteries/supercapacitors due to its substantial theoretical capacity, propitious lithiation potential, and large interlayer spacing. Nonetheless, it is encumbered by challenges of low electronic conductivity, momentous volume expansion (≈300%), and pernicious shuttle effect induced by soluble polyphosphides. Here a BP heterostructure covalent bonded by metallic antimony (Sb) is showed, which can promote the reaction dynamics of BP and greatly ameliorate the cycling performance. Robust P─Sb covalent bonds are methodically engineered to regulate the Femi level, endowing enhanced electronic conductivity. The in situ generated Li7SbO6 ionic conductor in the P/Sb interface during the lithiation process ensures the fast Li+ transport. Furthermore, Sb offers strong anchoring and chemical adsorption capability on soluble lithium polyphosphides, preventing the shuttle issue. As a result, a lithium‐ion capacitor (LIC) full‐cell based on Sb@BP/C anode demonstrates a superior energy density of 174.3 W h kg−1 and a power density of 23.7 kW kg−1, as well as exceptional reversible capacity retention. This work provides insights into the regulation of reaction kinetics and chemical adsorption capability of BP, offering guidance for designing high‐capacity and stable BP‐based anodes. [ABSTRACT FROM AUTHOR]

Lignin‐derived porous carbon (LPC) shows great potential as electrode material for supercapacitors. However, precise control over the pore structure during the conventional carbonization–activation process remains challenging. Here, a molecular‐level strategy to tailor the pore structure through tuning inter‐/intra‐molecular bonding of lignin in a pre‐carbonization process is shown. Based on operando pyrolysis analysis, a molecular evolution model is proposed to elucidate the relationship between pre‐carbonization and the resulting porosity of LPC. Lignin undergoes a condensation process with an increase of sp2‐hybridized carbon bonding during pre‐carbonization, causing the extension of polycyclic aromatic structure and leading to an increased mesopore volume in the final porous carbon. The variation in the content ratio of sp2‐ and sp3‐hybridized carbon bonding provides insights into the spatial structure evolution of pre‐carbonized lignin, which correlates well with changes in the porous structure of LPC. The LPCs show ultrahigh specific surface area up to 3219 m2 g−1 and tailored meso‐/micropore distribution. The lithium‐ion capacitor full‐cell tests demonstrate the great potential of LPCs in energy storage applications with superior energy density and power density. This work provides a feasible strategy to precisely design the microstructure of LPC, offering promising prospects for energy storage technologies. [ABSTRACT FROM AUTHOR]

The delicate structural engineering is widely acknowledged as a powerful tool for boosting the electrochemical performance of conversion‐type anode materials for lithium storage. Here, a general electrostatic self‐assembly strategy is proposed for the in situ synthesis of MnO nano‐cabbages on negatively charged reduced graphene oxide (rGO/MnO). The strong interfacial heterostructure and robust lithium storage mechanism related to fast Li+ diffusion kinetics and high Li‐adsorption ability of rGO/MnO heterostructure are confirmed through operando experimental characterizations and theoretical calculation. Owing to the rapid charge transfer, enriched reaction sites, and stable heterostructure, the as‐synthesized rGO/MnO anode delivers a high capacity (860 mAh g−1 at 0.1 A g−1), superior rate capability (211 mAh g−1 at 10 A g−1), and cycle stability. Notably, the as‐assembled flexible pouch cell of activated carbon//rGO/MnO solid‐state lithium‐ion capacitors (LICs) possesses an exceptional energy density of 194 Wh kg−1 and power density of 40.7 kW kg−1, both of which are among the highest flexible solid‐state LICs reported so far. Further, the LICs possess an ultralong life span with ≈77.8% retention after 10 000 cycles and extraordinary safety, demonstrative of great potential for practical applications. [ABSTRACT FROM AUTHOR]

2D 1T phase MoS2 (1T‐MoS2) nanosheet with metallic conductivity and expanded interlayer spacing is considered as a highly potential lithium storage electrode material but remains thermodynamic instability in aqueous media, seriously hindering the electrochemical performance. Herein, a versatile strategy is proposed for the preparation of thermodynamically stable 1T‐MoS2/MXene heterostructures with the aid of delaminated Ti3C2Tx MXene (d‐Ti3C2Tx) dispersion containing tetrabutylammonium hydroxide. The 2D d‐Ti3C2Tx provides more uniform nucleation sites for MoS2, and the TBA+ ions can intercalate into MoS2 to induce the phase conversion from semiconducting 2H to 1T. Moreover, the electrochemical advantages of 1T‐MoS2 and d‐Ti3C2Tx can be united by the construction of a well‐organized heterostructure. Outstanding rate performance is realized because of extra‐large interlayer space of 1T MoS2 with TBA+ intercalation and decreased energy barrier for fast Li+ diffusion. Subsequently, a lithium‐ion capacitor (LIC) is assembled based on 1T‐MoS2/d‐Ti3C2Tx as anode and hierarchically porous graphene nanocomposite with micro/mesoporous structure as a cathode. The LIC exhibits a large energy density up to 188 Wh kg−1, an ultra‐high power density of 13 kW kg−1, together with remarkable capacity retention of 83% after 5000 cycles. This study demonstrates the great promise of 1T‐MoS2/d‐Ti3C2Tx heterostructures as anode for high‐performance LICs. [ABSTRACT FROM AUTHOR]

Lithium-ion capacitors are envisaged as promising energy-storage devices to simultaneously achieve a large energy density and high-power output at quick charge and discharge rates. However, the mismatched kinetics between capacitive cathodes and faradaic anodes still hinder their practical application for high-power purposes. To tackle this problem, the electron and ion transport of both electrodes should be substantially improved by targeted structural design and controllable chemical doping. Herein, nitrogen-enriched graphene frameworks are prepared via a large-scale and ultrafast magnesiothermic combustion synthesis using CO2 and melamine as precursors, which exhibit a crosslinked porous structure, abundant functional groups and high electrical conductivity (10524 S m−1). The material essentially delivers upgraded kinetics due to enhanced ion diffusion and electron transport. Excellent capacities of 1361 mA h g−1 and 827 mA h g−1 can be achieved at current densities of 0.1 A g−1 and 3 A g−1, respectively, demonstrating its outstanding lithium storage performance at both low and high rates. Moreover, the lithium-ion capacitor based on these nitrogen-enriched graphene frameworks displays a high energy density of 151 Wh kg−1, and still retains 86 Wh kg−1 even at an ultrahigh power output of 49 kW kg−1. This study reveals an effective pathway to achieve synergistic kinetics in carbon electrode materials for achieving high-power lithium-ion capacitors. A large-scale and ultrafast combustion synthesis using CO2 as feedstock is demonstrated for the fabrication of nitrogen-enriched graphene frameworks (NGF) with high electrical conductivity, which delivers an upgraded kinetics due to the enhanced ion diffusion and electron transport. Lithium-ion capacitors based on NGF as both cathode and anode exhibit a high gravimetric energy density of 151 Wh kg−1 and power output of 49 kW kg−1. This study reveals an effective pathway to achieve synergistic kinetics in electrode materials for high-performance electrochemical energy storage. [ABSTRACT FROM AUTHOR]

The sluggish kinetics of battery-type anode limits the realization of high capacitance especially at elevated charge-discharge rates for lithium-ion capacitors (LICs). In this work, graphene wrapped carbon cages (G x P y) are obtained via a facile physical-confined pyrolysis approach from graphene oxide (GO)/polyvinylidene fluoride (PVDF), which exhibits great promise as a fast and large-capacity anode for LICs. The thermal degradation process analysis reveals that carbon cages with abundant mesopores derived from the dehalogenation of PVDF are formed spontaneously due to the HF releasing in the pyrolysis process with the aid of physical confined GO template. Hollow carbon cages could ameliorate the Li+ transport path, while 2D graphene serves as a conducting bridge connecting the isolated carbon cages to minimize the barrier of charge transfer. As a result, a LIC pouch-cell based on G x P y hierarchical carbon anode demonstrates high energy density and superior power density, as well as remarkable cycle life. This study may open a unique avenue for designing fast and large-capacity carbon anode and push the development of high-performance LICs. We report a physical-confined pyrolysis pathway to prepare hierarchical carbon anode composed of graphene wrapped carbon cages. Carbon cage structure can ameliorate the Li+ transport path, while graphene serves as a conducting bridge connecting the isolated carbon cages, resulting fast kinetics and large capacity as anode material. As a result, a LIC pouch-cell based on G x P y hierarchical carbon anode demonstrates impressive electrochemical performance. [Display omitted] • A physical-confined pyrolysis pathway is developed to prepare hierarchical carbon anode composed of graphene wrapped carbon cages. • The thermal degradation mechanism reveals that carbon cages are derived from the dehalogenation of PVDF due to the HF releasing in the pyrolysis process. • Cage structure can ameliorate Li + transport path, resulting fast kinetics and large capacity as anode material. [ABSTRACT FROM AUTHOR]

Heterogeneous layers structure delaminated Ti 3 C 2 T x /rGO is successfully prepared via cationic intermediates assisted self-assembly. Stable 2D structure and large interlayer space serve as a fast electrolyte ion transport channel, which enable the LIC with ultrahigh energy and power densities. [Display omitted] Two-dimensional (2D) material MXenes have been intensively concerned in energy-storage field due to these unique properties of metallic-like conductivity, good hydrophilicity and high volumetric capacity. However, the self-restocking of ultra-thin 2D materials seriously hinders these performances, which significantly inhibits the full exploitation of MXenes in the field of energy storage. To solve this issue, a strategy to prepare delaminated Ti 3 C 2 T x (MXene) nanoflakes/reduced graphene oxide (rGO) composites is proposed using the electrostatic self-assembly between positively charged Ti 3 C 2 T x with tetrabutylammonium ion (TBA+) modification and negatively charged graphene. The nanoflakes of Ti 3 C 2 T x /rGO are well dispersed and arranged in a face-to-face structure to effectively alleviate the self-restacking and provide more electroactive sites for accessible of electrolyte ions. The prepared delaminated Ti 3 C 2 T x /rGO anode shows a high reversible capacity up to 1394 mAh g−1 at a current density of 50 mA g−1. Moreover, a lithium-ion capacitor (LIC) was assembled with delaminated Ti 3 C 2 T x /rGO anode and activated carbon (AC) cathode which can exhibit a specific capacity of 70.7 F g−1 at a current density of 0.1 A g−1 and deliver an ultrahigh energy density of 114 Wh kg−1 at a relatively high power density of 3125 W kg−1. These good electrochemical performances demonstrate the potential of delaminated Ti 3 C 2 T x /rGO as an anode material for lithium-ion capacitors. [ABSTRACT FROM AUTHOR]

• MXene derived quantum dot complexes are fabricated. • Nb vacancies are implanted into T-Nb 2 O 5 nanoparticles after oxidative etching. • The T-Nb 2 O 5 /rGO with cation vacancies delivers fast multi-electron redox reaction. • The LIC based on T-Nb 2 O 5 /rGO shows 123.7 Wh/kg at 1.29 kW/kg and long cycle life. Orthorhombic niobium pentoxide (T-Nb 2 O 5) is widely acknowledged as a fast pseudocapacitive material. Nevertheless, its application is hindered by the narrow voltage window (1–3 V vs. Li/Li+) that arises from irreversible phase transformation and sluggish kinetics during deep lithiation. Herein, we demonstrate a unique method for introducing Nb vacancies in T-Nb 2 O 5 nanoparticles via amine-assisted oxidative etching of Nb 2 CT x MXene, providing extra storage sites and improving structural flexibility by introducing cationic defects. Subsequently reduced graphene oxide (rGO) is employed as substrate to disperse T-Nb 2 O 5 nanoparticles and construct T-Nb 2 O 5 /rGO nanohybrids. Multiple characterizations and computational simulations demonstrate that the resulting T-Nb 2 O 5 /rGO hybrid anode exhibits rapid and stable multi-electron transfer lithium storage. Owing to the enrichment of Nb vacancies and nanoparticle morphology, even when voltage window of 0.01–3 V (vs. Li/Li+) is extended, T-Nb 2 O 5 exhibits a pseudocapacitive mechanism and integrity of partial crystal structure; effectively tackling the structural collapse and sluggish kinetics of T-Nb 2 O 5. Consequently, the T-Nb 2 O 5 /rGO anode shows a superior rate capacity (148 mAh/g at 10 A/g) and cycling stability (3000 cycles at 5 A/g). Remarkably, the assembled lithium-ion capacitors achieve a high energy density of 123.7 Wh/kg, a power density of 22.5 kW/kg, and a capacity retention of 83.6% after 20,000 cycles. [ABSTRACT FROM AUTHOR]