A N-CoSe/CoSe_(2)-C@Cu hierarchical architecture as a current collector-integrated anode for potassium-ion batteries

The highly reversible insertion/extraction of large-radius K^+into electrode materials remains a tough goal,especially for con version-type materials.Herein,we design a current collector-integrated electrode(N-CoSe/CoSe_(2)-C@Cu) as an advanced anode for potassium-ion battery(PIBs).The conductive CoSe/CoSe_(2) heterojunction with rich Se vacancy defects,conductive sp^2 N-doped carbon layer,and the elastic copper foil matrix can greatly accelerate the electron transfer and enhance the structural stability.Consequently,the well-designed N-CoSe/CoSe_(2)-C@Cu current collector-integrated electrode displays enhanced potassium storage performance with regard to a high capacity(325.1 mAh·g^(-1) at 0.1 A·g^(-1) after 200cycles),an exceptional rate capability(223.5 mAh·g^(-1) at2000 mA·g^(-1)),and an extraordinary long-term cycle stability(a capacity fading of only 0.019% per cycle over1200 cycles at 2000 mA·g^(-1)).Impressively,ex situ scanning electron microscopy(SEM) characterizations prove that the elastic structure of copper foil is merged into the cleverly designed N-CoSe/CoSe_(2)-C@Cu heterostructure,which buffers the deformation of structure and volume and greatly promotes the cycle life during the potassium/depotassium process.

OPTIMAL DESIGN OF HOUSING ATTICS WITH INTEGRATED SOLAR COLLECTORS

In order to reduce the increasing energy consumption for the domestic demands of existing single-family housing and take advantage of frequent building enlargements,this paper presents a methodology and supporting software tool for determining the optimal design configuration of an attic with integrated solar collectors.The analysis procedure is based on parametric modeling,energy simulation and the use of evolutionary algorithms for finding optimal designs.It has been implemented as a Web-platform for public use that provides users with a proposal of an attic shape with maximum solar energy collection,maximum living space and minimum construc-tion envelope for each house according its size and orientation.The attic integrates PV,thermal and hybrid solar panels on one side of the roof.This paper describes the methodology and software design,asssment of the Web-platform usage and case-studies to verify its behavior.In a matter of minutes,the Web-platform enables users to select a specific attic design for each house that has integrated solar collectors that can produce energy to cover almost 100%of domestic energy consumption.The attics designed provide a nearly 30%increase in living space through the extension of one to four rooms,and the construction cost of the envelope is similar to that of a standard housing extension.