Reconstructed Orthorhombic V2O5 Polyhedra for Fast Ion Diffusion in K-Ion Batteries

Abstract

To unlock the compact structure of a-V 2 O 5 for the diffusion of K + , we developed single-crystalline bilayered d-K 0.51 V 2 O 5 nanobelts via reconstruction of a-V 2 O 5 . Benefiting from the large interlayer space and optimized growth orientation, d-K 0.51 V 2 O 5 exhibits suitable accommodation sites and fast diffusion paths for K + , enabling high capacity and rate capability. Additionally, the achievement of a high-energy-and high-power-density full K-ion battery proves its feasibility in large-scale energy storage systems. SUMMARYPotassium-ion batteries (KIBs) are a promising alternative to lithium-ion batteries because of the abundance, low cost, and redox potential of K; however, the significantly larger radius of K + inevitably destabilizes the crystal structure of the cathode material, impeding the diffusion of K + . Here, to lower the insertion energetics and diffusion barriers of K + , we synthesizedd-K 0.51 V 2 O 5 nanobelts (KVOs) with a large interlayered structure and optimized growth orientation by reconstructing the V-O polyhedra of orthorhombic V 2 O 5 ; these exhibited a high average voltage (3.2 V), high capacity (131 mAh g À1 ), and superior rate capability even at 10 A g À1 . By coupling the electrochemical experiments with theoretical calculations, we found that the excellent K-ion storage performance of KVO is attributed to its large interlayered structure and unique 1D morphology. Additionally, we assembled a full KIB composed of KVO and graphite with high energy and power densities, proving its feasibility as a promising new battery.

Surface‐Engineered Black Niobium Oxide@Graphene Nanosheets for High‐Performance Sodium‐/Potassium‐Ion Full Batteries

“…Fabrication of K‐ion full battery is more difficult than the assembly of Na‐ion full battery because of the larger size of K‐ions . Figure a displays a schematic of the full battery structure with black Nb 2 O 5− x @rGO and K 0.5 V 2 O 5 during the K‐ion uptake/release over a voltage range of 1.0–3.3 V. The positive electrode is a K 0.5 V 2 O 5 with a layered skeleton with K‐ion storage derived from the V 5+ /V 4+ redox couples, whereas the negative electrode is the black Nb 2 O 5− x @rGO that holds K‐ions in its amorphized niobium oxide layer after initial discharge/charge cycle. During the charging process, K‐ions are extracted from the K 0.5 V 2 O 5 cathode and inserted into the black Nb 2 O 5− x @rGO anode .…”

Cylindroid‐Like Li4Ti5O12 Mesocrystals for High‐Rate and Long‐Life Lithium‐Ion Battery Anodes

“…Fast‐charging and long‐term cycling life are two indispensable aspects for next‐generation lithium ion batteries (LIBs), especially in electric vehicles (EVs) or hybrid electric vehicles (HEVs) . However, commercial graphite anode unable to meets these requirements owing to its compromised rate capability arising from low ionic/electronic diffusion coefficient and severe safety issues originating from the lithium dendrite formation .…”

Empowering organic‐based negative electrode material based on conjugated lithium carboxylate through molecular design

“…Nevertheless, the electroactive compounds used as an electrode in these systems are exclusively inorganic materials based on Co, Mn, Fe, Ni, V, which are exhaustible, difficult to recycle and sometimes toxic . In parallel to the eco‐conception of electroactive materials and the recycling of present Li‐ion batteries constituents, a promising solution to overcome these problems is to use renewable resources, such as organic compounds from inedible agro‐resources and/or “green” sustainable synthesis processes taking into account the resource aspect and ecological sustainability, to create sustainable, efficient, and easy recycling electrical energy‐storage systems . For now, the organic‐batteries field benefits from more than ten years of intensive research and is still an active research area .…”