生物质是世界上取之不尽用之不竭的可再生资源，将其制备成生物质炭，既节约

Biomass is an inexhaustible renewable resource in the world, and its preparation into biomass charcoal not only saves costs but also realizes the sustainable development of energy. Sisal fiber is a low-cost, renewable biomass. Sisal fiber made of sisal fiber carbon as an electrode material for energy storage devices can not only expand the use of sisal fiber, but also reduce the cost of electrode materials. . However, when pure sisal fiber carbon (SFAC) is used as an energy storage material, it has the first shortcomings of low coulombic efficiency, large irreversible capacity, voltage lag, and weak current charging and discharging capabilities. To overcome these shortcomings and further improve the electrochemical performance of SFAC, In this subject, by co-doping N, P elements in SFAC, N, P element co-doped modified carbon materials were obtained, and the structure, morphology and electrochemical performance were characterized by XRD, SEM, Raman spectroscopy and other techniques. <br>By exploring the effects of dopant types ((NH4) 2HPO4, (NH4) 3PO4, NH4H2PO4), the mass ratio of dopant to SFAC, calcination temperature and other conditions on the structure, morphology and electrochemical performance of SFAC, N , P element co-doped sisal fiber carbon (N, P-SFAC) lithium ion battery anode material the best preparation process conditions. <br>The dopant is NH4H2PO4, the mass ratio of SFAC to dopant is 1: 4, and the doping calcination temperature is 950 ℃. Under these conditions, the prepared N, P-SFAC has a sheet-like porous, honeycomb-like morphology, the pores are mesoporous, the pore size distribution is 5-12 nm, and the specific surface area is greater than pure SFAC, up to 2040.97m2g-1; As a negative electrode material for lithium ion batteries, it has more excellent electrochemical performance than pure SFAC. At a current density of 1A / g, the specific capacity is as high as 2100mAh / g for the first time. After 30 cycles, it is still stable at 861mAh / g, with good Cyclic stability, the first Coulomb efficiency is 55.3%, the impedance is small, 48Ω, and it has good conductivity.

Biomass is an inexhaustible renewable resource in the world, which is prepared into biomass carbon, which can not only save cost and realize the sustainable development of energy. Sword hemp fiber is a kind of low-cost, renewable biomass, the sword hemp fiber prepared into sword hemp fiber carbon as an electrode material of energy storage device, can not only expand the use of swords and hemp fiber, but also reduce the cost of electrode material. However, pure sword hemp fiber carbon (SFAC) as a energy storage material, there is the first coulomb low efficiency, irreversible capacity, voltage lag, large current charge and discharge capacity is weak and other shortcomings, in order to overcome these shortcomings, and further improve the electrochemical properties of SFAC, this topic through the SFAC doped N, P elements, N, P elements of mixed carbon materials, using XRD, SEM, Raman spectroscopy and other chemical properties.<br>By exploring the effects of the types of doping agents (NH4) 2HPO4, NH4 3PO4, NH4H2PO4), doping agentand and SFAC quality ratio, calcination temperature and other conditions on the structure, shape and electrochemical properties of SFAC, the best preparation process conditions for N, P-elements mixed with swords hemp carbon (N, P-SFAC) lithium-ion battery negative materials were obtained.<br>The doping agent is NH4H2PO4, the quality ratio of SFAC to doping agent is 1:4, and the doping calcination temperature is 950 degrees C. Under this condition, the prepared N,P-SFAC has a flaky, hive-like shape, the gap is a mesoporous structure, the aperture is distributed at 5-12nm, the surface area is greater than the pure SFAC, up to 2040.97m2g-1; Better electrochemical performance, in the current density of 1A/g, the first than the capacity of up to 2100mAh/g, after 30 cycles, still stable to maintain at 861mAh/g, with good circulation stability, the first Cullen efficiency of 55.3%, small impedance, for 48 o, with good conductivity.

Biomass is an inexhaustible renewable resource in the world. The preparation of biomass carbon can not only save cost but also realize the sustainable development of energy. Sisal fiber is a kind of cheap and renewable biomass. The preparation of sisal fiber into sisal fiber carbon as the electrode material of energy storage device can not only expand the use of sisal fiber, but also reduce the cost of electrode material.. However, pure sisal fiber carbon (SFAC) as energy storage material has the disadvantages of low coulomb efficiency, large irreversible capacity, voltage lag and weak charging and discharging capacity at high current for the first time. In order to overcome these disadvantages and further improve the electrochemical performance of SFAC, N was obtained by CO doping n, P elements in SFAC, The structure, morphology and electrochemical properties of the modified carbon were characterized by XRD, SEM and Raman spectroscopy.<br>By exploring the influence of dopant types (NH4) 2HPO4, (NH4) 3PO4, NH4H2PO4), mass ratio of dopant to SFAC, calcination temperature and other conditions on the structure, morphology and electrochemical performance of SFAC, the best preparation conditions of negative electrode materials of sisal fiber carbon (n, p-sfac) were obtained.<br>The dopant is NH4H2PO4, the mass ratio of SFAC to dopant is 1:4, and the doping calcination temperature is 950 ℃. Under this condition, the prepared n, P-sfac has the shape of flake, porous and honeycomb like. The pore size distribution is 5-12nm. The specific surface area of p-sfac is larger than that of pure SFAC, up to 2040.97m2g-1. As the anode material of lithium-ion battery, p-sfac has better electrochemical performance than pure SFAC. At the current density of 1A / g, the specific capacity of p-sfac is up to 2100mAh / g for the first time. After 30 cycles, it is still stable at 861mah / g, with good performance The first coulomb efficiency is 55.3%, the impedance is small, 48 Ω, and it has good conductivity.<br>